Inhibitor of IGFBP3/TMEM219 Axis and Diabetes

ABSTRACT

The present invention relates to the role of the IGFBP3/TMEM219 axis in the onset of diabetes and the related use of IGFBP3/TMEM219 axis inhibitors for the treatment and/or prevention of diabetes. The invention also relates to a method to identify a subject at risk of developing Type 1 and/or Type 2 diabetes and relative kit.

TECHNICAL FIELD

The present invention relates to the role of the IGFBP3/TMEM219 axis in the onset of diabetes and the related use of IGFBP3/TMEM219 axis inhibitors for the treatment and/or prevention of diabetes. The invention also relates to a method to identify a subject at risk of developing Type 1 and/or Type 2 diabetes and relative kit.

BACKGROUND ART

Gastrointestinal disorders, consisting of gastroparesis, abdominal distension, irritable bowel syndrome and fecal incontinence, are common in individuals with type 1 diabetes (T1D)(1993). Indeed up to 80% of individuals with long-standing T1D, who are generally affected by several diabetic complications including end stage renal disease (ESRD)(1993; Atkinson et al., 2013; Fiorina et al., 2001), show intestinal symptoms. The presence of these gastrointestinal symptoms, known as diabetic enteropathy (DE), significantly reduces the quality of life (1993; Atkinson et al., 2013; Camilleri, 2007; Talley et al., 2001) and has a largely unknown pathogenesis (Feldman and Schiller, 1983). Preclinical studies showed significant derangement of the intestinal mucosa morphology in diabetic rodents (Domenech et al., 2011; Zhao et al., 2003), suggesting that in T1D intestinal homeostasis may be altered; however, little data are available in humans. The intestinal epithelium is maintained by intestinal stem cells and their niche, which respond to physiological stress and to environmental injury (Barker, 2014; Medema and Vermeulen, 2011). Colonic stem cells (CoSCs), located at the crypt base of the large intestine and expressing the ephrin B receptor 2 (EphB2), leucine-rich repeat containing G protein-coupled receptor 5 (LGR5), h-TERT and aldehyde dehydrogenase (Aldh), among other markers (Carlone and Breault, 2012; Carpentino et al., 2009; Jung et al., 2011; Sato and Clevers, 2013), constitute with the local microenvironment the CoSC niche (van der Flier and Clevers, 2009; Zeki et al., 2011). Recent studies have established conditions that recapitulate many features of intestinal homeostasis and generate normal self-renewing large crypt organoids in vitro, or so-called “mini-guts” (Sato and Clevers, 2013). Whether systemic factors, such as circulating hormones, serve to control the CoSCs remains to be established (Stange and Clevers, 2013).

The treatment of gastrointestinal disorders, in particular diabetic enteropathy includes symptomatic drugs and reliever medications for diarrhea, abdominal pain, constipation, and dyspepsia. Up to date there is no specific treatment available for diabetic enteropathy.

The diagnosis of gastrointestinal disorders, in particular diabetic enteropathy includes colon endoscopy, gastric endoscopy, anorectal manometry, esophageal manometry and analysis of fecal samples, evaluation of peripheral cancer markers (i.e. CEA, Ca 19.9, alpha-fetoprotein, Ca125) and of celiac markers. None of the aforementioned method is capable of providing a certain diagnosis of diabetic enteropathy.

WO 2011133886 and WO2007024715 disclose a therapeutic composite in the form of a IGFBP3 binding antibody.

WO0187238 relates to an anticancer pharmaceutical composition comprising a therapeutically effective TMEM219, in particular for the treatment of colon cancer.

WO 2014089262 discloses the use of IGFBP3 as a marker of diagnosis of chronic inflammation (obesity) disorders (in particular, inflammatory bowel disease such as UC and Crohn's disease and colon cancer).

U.S. Pat. No. 6,066,464 relates to an immunoassay for the detection of IGFBP3 on a solid support that is paper.

WO2013152989 relates to the use of IGFBP3 as a biomarker of colorectal cancer.

WO0153837 discloses a method of monitoring or diagnosing disease conditions that involve measuring a combination of tumor markers and at least one component of the IGF axis. IGFBP3 is proposed as a marker of colon tumors.

Type 1 diabetes (T1D) has historically been regarded as a T cell-mediated autoimmune disease, resulting in the destruction of insulin-producing pancreatic beta cells (Bluestone et al., 2010; Eisenbarth, 1986). According to this perspective, an initiating factor triggers the immune response against autoantigens, and the subsequent newly activated autoreactive T cells target and further destroy the pancreatic islets and insulin-producing beta cells (Bluestone et al., 2010). Whether destruction of beta cells is solely determined by the autoimmune attack or whether other mechanisms such as paracrine modulation, metabolic deregulation, non-immune beta cell apoptosis and halted beta cell regeneration contribute to T1D pathogenesis is now a matter of debate (Atkinson and Chervonsky, 2012; Atkinson et al., 2015). Recently, it has been observed that environmental factors are required to initiate the autoimmune response in T1D, particularly viral infections (Filippi and von Herrath, 2008), and studies of the impact of gut microbiota have revealed that enteroviruses are involved in activating autoreactive T cells (McLean et al., 2015). Ongoing studies are also focused on other environmental risk factors such as diet, neonatal exposure to milk and gluten, and age at weaning, suggesting that a new approach to study the pathogenesis of T1D is gradually emerging (McLean et al., 2015), such that genetic factors are no longer considered to be the sole determinant of T1D (Alper et al., 2006) (Oilinki et al., 2012). Moreover, the efficacy of immunotherapeutic strategies, which have been considered in the last decade to be the principal prospect for establishing a cure for T1D, is now being questioned (Ben Nasr et al., 2015a). While targeting the autoimmune response using an immunosuppressive treatment or a pro-regulatory regimen was shown to be satisfactory in rodents, such strategies conversely achieved insulin independence in a negligible number of T1D individuals (Atkinson et al., 2015). In addition to underscoring the difference between animal models and humans, these data also shed light on the fact that investigation of the immune response primarily examined immune events occurring in the periphery, while little is known with respect to the disease process that occurs within islets and particularly in beta cells. In this regard, the discovery of novel factors involved in the initiation/facilitation of beta cell loss in T1D will be of significant value. Such discoveries may pave the way for novel therapeutic approaches capable of halting or delaying the very first phase of the disease. Then, there is still the need for alternative treatment for T1D and T2D.

WO2008153788 claims a method to inhibit or reduce IGFBP3 levels to treat insulin resistance or TD2, wherein the inhibitor is a nucleic acid complementary to IGFBP3 mRNA or an antibody that binds IGFBP3, anti IGFBP-3. The document is silent about the IGFBP3/TMEM219 axis. Muzumdar et al. (Muzumdar et al., 2006) discloses that IGFBP3 acts as an insulin antagonist through a central mechanism leading to a reduced peripheral glucose uptake. This document does not disclose the inhibition of the IGFBP3/TMEM219 axis.

WO9739032 claims the use of an IGFBP3 inhibitor to treat diabetes, wherein the inhibitor prevents IGFBP-3 binding to IGF-1. Inhibition of IGFBP3/TMEM219 axis is not contemplated. D'Addio et al., (2015) indicates that eco-TEM219 normalize circulating IGF-I/IGFBP3 levels. WO2007024715 relates to the use of engineered multivalent and multispecific binding proteins, namely dual variable domain immunoglobulins, which bind two different antigens or target peptides using a single middle linker and are bispecific. The document mentions among the numerous target proteins, IGFBP3 in combination with other members of the family.

WO2011133886: relates to a method of generating antibodies and other multimeric protein complexes, namely heteromutlimeric proteins, capable of specifically binding to more than one target. IGFBP3 may represent a potential target.

SUMMARY OF THE INVENTION

Whether systemic factors serve to control the homeostasis of colonic epithelium and of colonic stem cells (CoSCs) remains unclear. The inventors hypothesize that a circulating “hormonal” dyad controls CoSCs and is disrupted in long-standing type 1 diabetes (T1D) leading to diabetic enteropathy (DE). Individuals with long-standing T1D exhibited abnormalities of intestinal mucosa and CoSCs, and failure to generate in vitro mini-guts. Serum proteomic profiling revealed altered circulating levels of insulin-like growth factor 1 (IGF-I) and its binding protein-3 (IGFBP3) in long-standing T1D individuals, with evidences of an increased hyperglycemia-mediated IGFBP3 hepatic release. IGFBP3 prevented mini-gut growth in vitro via a TMEM219-dependent/caspase-mediated IGF-I-independent effect and disrupted CoSCs in preclinical models in vivo. The restoration of normoglycemia in long-standing T1D, with kidney-pancreas transplantation, and the treatment with an ecto-TMEM219 recombinant protein in diabetic mice, re-established CoSCs by restoring appropriate IGF-I/IGFBP3 circulating levels. The peripheral IGF-I/IGFBP3 dyad controls CoSCs and is dysfunctional in DE.

Here the inventors demonstrate that individuals with long-standing T1D and DE have altered CoSCs and show increased levels of IGFBP3. Administration of IGFBP3 alters CoSC regenerative properties and mucosa morphology in vitro and in vivo, in a preclinical model of DE, by quenching circulating IGF-I and by exerting a TMEM219-dependent/caspase-mediated toxic effect on CoSCs. Finally, a new ecto-TMEM219 recombinant protein, based on the extracellular domain of the IGFBP3 receptor (TMEM219) was generated. ecto-TMEM219 quenches peripheral IGFBP3 and prevents its binding to IGFBP3 receptor, TMEM219. Then, targeting IGFBP3 with such ecto-TMEM219 recombinant protein, expressed on CoSCs, abrogates IGFBP3 deleterious effects in vitro and in vivo.

The present invention reports compelling data showing that IGFBP3 release is increased in individuals at high-risk for T1D and T2D. Interestingly, the inventors have discovered that the IGFBP3 receptor, TMEM219, is expressed in a beta cell line and on murine/human islets, and that its ligation by IGFBP3 is toxic to beta cells, raising the possibility of the existence of an endogenous beta cell toxin. This suggests that beta cell toxin(s) [betatoxin(s)] may be involved in the pathogenesis of TD1, in particular in the early phase, when islet/beta cell injuries may facilitate the exposure of autoantigens to immune cells, thus creating a local inflamed environment and a sustained immune reaction. Interestingly, authors have observed elevated levels of IGFBP3 in pre-T2D and in T2D individuals as well, suggesting that a potential role for this axis is also evident in T2D.

The inventors have also observed that IGFBP3 may induce apoptosis of beta cells and of murine/human islets in vitro in a caspase 8-dependent manner. Finally, the newly generated recombinant ecto-TMEM219 protein, based on the TMEM219 extracellular domain, capable of quenching IGFBP3, prevents its signaling via TMEM219 on pancreatic beta cells. Ecto-TMEM219 treatment reduces beta cell loss, improves islet insulin content and glycometabolic control in murine models of diabetes (T1D and T2D) in vivo, while in vitro it protects islets and beta cells from IGFBP3-induced apoptosis. The inventors demonstrate that IGFBP3 is an endogenous peripheral beta cell toxin (or betatoxin) that is increasingly released in individuals at high-risk for diabetes (T1D and T2D). Concomitant expression of the IGFBP3 receptor (TMEM219) on beta cells initiates/facilitates beta cell death, thus favoring diabetes onset/progression.

In other words, the invention is based on the finding that TMEM219, the IGFBP3 receptor that mediates IGFBP3/IGF1 independent detrimental effects, is expressed on pancreatic islets and beta cells; moreover, targeting the IGFBP3/TMEM219 axis with ecto-TMEM219 re-establishes appropriate IGFBP3 signaling in diabetic mice and prevents beta cell loss and preserves islet morphology, thereby confirming the critical role of the IGFBP3/TMEM219 axis in favoring beta cell loss in diabetes.

The present therapeutic approach, based on the inhibition of IGFBP3/TMEM219 axis, may overcome the limits of the current therapies for T1D and T2D as it could prevent the beta cell damage and the consequent reduced or abolished insulin secretion that leads to the development of diabetes.

Then, the advantages of the present invention over prior art treatments are:

-   -   Prevention of beta cell and islets destruction     -   Protection of beta cell mass and of insulin-producing cells     -   Prevention of major diabetes complications     -   Limitation of autoimmune attack towards pancreatic islets in T1D     -   Prevention of insulin resistance in T2D and     -   No requirement for immunotherapy in T1D.

Then the invention provides an inhibitor of IGFBP3/TMEM219 axis for use in the treatment and/or prevention of diabetes in a subject.

Preferably said inhibitor is selected from the group consisting of:

-   -   a) a polypeptide;     -   b) a polynucleotide coding for said polypeptide or a         polynucleotide able to inhibit IGFBP3/TMEM219 axis;     -   c) a vector comprising or expressing said polynucleotide;     -   d) a host cell genetically engineered expressing said         polypeptide or said polynucleotide;     -   e) a small molecule;     -   f) a peptide, a protein, an antibody, an antisense         oligonucleotide, a siRNA, antisense expression vector or         recombinant virus or any other agent able to inhibit or         IGFBP3/TMEM219 axis.

Preferably said inhibitor is the receptor TMEM219 or a fragment thereof.

Preferably the fragment of TMEM219 is a fragment comprising an extracellular domain of TMEM219.

In a preferred embodiment the inhibitor is ecto-TMEM219. Preferably the inhibitor is soluble.

Preferably said inhibitor is a fusion protein TMEM219-Ig, preferably said fusion protein quenches circulating IGFBP3 and prevents its binding to TMEM219.

Preferably the inhibitor is an anti-IGFBP3 antibody, preferably said antibody selectively blocks the TMEM219-binding site;

Preferably said inhibitor is an anti-TMEM219 antibody, preferably said antibody occupies the IGFBP3 binding site of TMEM219 receptor thus preventing IGFBP3 binding.

More preferably said inhibitor is an oligonucleotide complementary to IGFBP3 mRNA.

In a preferred embodiment the diabetes is Type-1 or Type-2 diabetes.

Still preferably the subject is selected from the group consisting of: a subject at risk of developing Type-1 and/or Type-2 diabetes, a subject with early stage Type-1 and/or Type-2 diabetes.

The present invention also provides a pharmaceutical composition for use in the treatment and/or prevention of diabetes comprising the inhibitor of the invention and pharmaceutically acceptable carriers. Preferably the pharmaceutical composition further comprises a therapeutic agent.

Preferably the therapeutic agent is selected from the group consisting of: insulin in any form, Pramlintide (Symlin), angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs), Aspirin, Cholesterol-lowering drugs. Metformin (Glucophage, Glumetza, others), Sulfonylureas (glyburide (DiaBeta, Glynase), glipizide (Glucotrol) and glimepiride (Amaryl), Meglitinides (for instance repaglinide (Prandin) and nateglinide (Starlix)), Thiazolidinediones (Rosiglitazone (Avandia) and pioglitazone (Actos) for examples), DPP-4 inhibitors (sitagliptin (Januvia), saxagliptin (Onglyza) and linagliptin (Tradjenta)), GLP-1 receptor agonists (Exenatide (Byetta) and liraglutide (Victoza)), SGLT2 inhibitors, examples include canagliflozin (Invokana) and dapagliflozin (Farxiga).

The present invention also provides a method to identify a subject at risk of developing Type-1 and/or Type-2 or to monitor the response to a therapeutic treatment in a subject comprising:

-   -   a) measuring the amount of the protein IGFBP3 or the amount of         the polynucleotide coding for said protein in a biological         sample obtained from the subject;     -   b) comparing the measured quantity of the protein IGFBP3 or         measured quantity of the polynucleotide coding for said protein         to a control amount, wherein if the measured quantity is higher         than the control amount, the subject is at risk of developing         Type-1 and/or Type-2 diabetes.

Preferably the quantity of IGFBP3 is measured by an antibody.

More preferably the biological sample is selected from the group consisting of: serum, urine, cell culture supernatant.

The present invention also provides a kit comprising means to measure the amount of the protein IGFBP3 and/or means to measure the amount of the polynucleotide coding for said protein and optionally, control means for use in the method of the invention.

In the present invention inhibiting the IGFBP3/TMEM219 axis means blocking IGFBP3 binding to TMEM219, for instance by quenching IGFBP3 from the circulation, it also means blocking the IGFBP3-binding site of TMEM219, blocking IGFBP3 binding site on TMEM219. It further means inhibiting TMEM219 function and/or expression and/or signaling, this may be achieved for instance by silencing TMEM219 expression, in particular with SiRNA or oligonucleotides. It also means inhibiting the function and/or expression of IGFBP3.

According to the invention, an inhibitor of IGFBP3 binding to TMEM219 can be one of the following molecules:

-   -   Soluble Ecto-TMEM219 (extracellular portion of TMEM219) which         neutralizes circulating IGFBP3;     -   Fusion protein TMEM219-Ig, a Fc-based fusion protein composed of         an immunoglobulin Fc domain that is directly linked to TMEM219         peptide or to its extracellular portion, which quenches         circulating IGFBP3 and prevents its binding to TMEM219 expressed         on beta cells;     -   Anti-IGFBP3 antibody that selectively blocks the TMEM219-binding         site;     -   Anti-TMEM219 antibody, which occupies the IGFBP3 binding site of         TMEM219 receptor thus preventing IGFBP3 binding (having         antagonistic activity with respect to IGFBP3)     -   Oligonucleotides complementary to IGFBP3 mRNA

In the present invention the patient that may be treated are individuals who are at risk for developing T1D (autoimmune diabetes, based on the presence of peripheral anti-islet autoantibodies or genetic predisposition or familiar predisposition or altered beta cell function) or T2D (non autoimmune diabetes based on the evidence of an impaired fasting glucose and/or impaired glucose tolerance without fulfilling the criteria for the diagnosis of diabetes), or individuals who develop T1D or T2D in any stage of the disease, in particular a subject with early stage Type-1 and/or Type-2 diabetes, with the purpose of protecting beta cells from further destruction. The presence of any degree of preserved beta cells is the only requirement for assessing the successful therapy.

The expression of IGFBP3 may be measured by means of RT-PCR on tissues and cells, Western blot on tissues and cells, Immunohistochemistry on tissues, Immunofluorescence on tissue and cells. Levels of IGFBP3 in biological fluids can be measured by immune-targeted assays and proteomic analysis.

The function of IGFBP3 may be measured by means of detecting Caspases 8 and 9 expression on target cells using RT-PCR, microarrays, by co-culturing target cells/structures with Pan Caspase inhibitor, Caspases 8 and 9 inhibitors and measuring live cells/structures.

In the present invention “inhibit or block the interaction of IGFBP3 with its receptor TMEM219” means quenching circulating IGFBP3 and preventing its binding to TMEM219 receptor expressed on pancreatic islets and beta cells. The IGFBP3-TMEM219 binding could be prevented also by the use of an IGFBP3-blocking antibody. In addition, a TMEM219 blocking antibody could bind TMEM219 receptor thus rendering the receptor unavailable when IGFBP3 comes from the circulation.

The inhibitor of the invention may be the receptor TMEM219 (MGNCQAGHNLHLCLAHHPPLVCATLILLLLGLSGLGLGSFLLTHRTGLRSPDIPQDWV SFLRSFGQLTLCPRNGTVTGKWRGSHVVGLLTTLNFGDGPDRNKTRTFQATVLGSQMG LKGSSAGQLVLITARVTTERTAGTCLYFSAVPGILPSSQPPISCSEEGAGNATLSPRMGEE CVSVWSHEGLVLTKLLTSEELALCGSRLLVLGSFLLLFCGLLCCVTAMCFHPRRESHWS RTRL, SEQ ID No. 1) or a fragment thereof.

In particular the fragment of TMEM219 is designed such as to block/prevent IGFBP3 access and/or binding to TMEM219, it has a smaller molecular weight, it contains five cysteins that form disulfide bridges and a globular structure. Preferably the fragment is at least 50 amino acid long, preferably 100 amino acid long, still preferably 120 amino acid long, yet preferably 150 amino acid long, preferably at least 160 amino acid long.

In a preferred embodiment the fragment is at least 162, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235 amino acid long. Preferably the fragment has at least 65% identity with the sequence of TMEM219, preferably at least 70%, 75%, 80%, 85%, 90%, 95% or 99% identity with the sequence of TMEM219.

Preferably the fragment of TMEM219 is a fragment of an extracellular domain of TMEM219 (ecto-TMEM219), in particular the fragment comprises the sequence: THRTGLRSPDIPQDWVSFLRSFGQLTLCPRNGTVTGKWRGSHVVGLLTTLNFGDGPDR NKTRTFQATVLGSQMGLKGSSAGQLVLITARVTTERTAGTCLYFSAVPGILPSSQPPISC SEEGAGNATLSPRMGEECVSVWSHEGLVLTKLLTSEELALCGSR (SEQ ID No. 2).

Preferably the fragment of TMEM219 is an extracellular domain of TMEM219, in particular the fragment comprises the sequence: SFLLTHRTGLRSPDIPQDWVSFLRSFGQLTLCPRNGTVTGKWRGSHVVGLLTTLNFGDG PDRNKTRTFQATVLGSQMGLKGSSAGQLVLITARVTTERTAGTCLYFSAVPGILPSSQPP ISCSEEGAGNATLSPRMGEECVSVWSHEGLVLTKLLTSEELALCGSR (SEQ ID No. 3) Preferably the fragment of TMEM219 consists of: THRTGLRSPDIPQDWVSFLRSFGQLTLCPRNGTVTGKWRGSHVVGLLTTLNFGDGPDR NKTRTFQATVLGSQMGLKGSSAGQLVLITARVTTERTAGTCLYFSAVPGILPSSQPPISC SEEGAGNATLSPRMGEECVSVWSHEGLVLTKLLTSEELALCGSR (SEQ ID No. 2).

Preferably the fragment of TMEM219 consists of: SFLLTHRTGLRSPDIPQDWVSFLRSFGQLTLCPRNGTVTGKWRGSHVVGLLTTLNFGDG PDRNKTRTFQATVLGSQMGLKGSSAGQLVLITARVTTERTAGTCLYFSAVPGILPSSQPP ISCSEEGAGNATLSPRMGEECVSVWSHEGLVLTKLLTSEELALCGSR (SEQ ID No. 3).

In the present invention TMEM219 is preferably eukaryote TMEM219, preferably a mammal TMEM219, still preferably human TMEM219.

The interaction of IGFBP3 with TMEM219 may be measured by means of indirect assessment of the effects of IGFBP3 on target cells (increased Caspase 8 and 9 expression with RT-PCR), direct assessment of IGFBP3-IGFBP3-receptor (TMEM219) binding with Liquid or Solid Phase Ligand Binding Assays (i.e. immunoprecipitation, RT-PCR, immunoassays) and Non-radioactive Ligand Binding Assays.

In the present invention “long-standing T1D” means a history of type 1 diabetes longer than 15 years associated with the development of diabetic complications.

In a preferred aspect of the invention, the inhibitor is an antibody or synthetic or recombinant derivative thereof. Said antibody is preferably a monoclonal or polyclonal antibody, or synthetic or recombinant derivatives thereof, more preferably said antibody being a humanized monoclonal antibody.

Preferably, said polynucleotide is a RNA or DNA, preferably a siRNA, a shRNA, a microRNA or an antisense oligonucleotide.

In a preferred embodiment, the above vector is an expression vector selected from the group consisting of: plasmids, viral particles and phages.

Preferably, said host cell is selected from the group consisting of: bacterial cells, fungal cells, insect cells, animal cells, plant cells, preferably being an animal cell, more preferably a human cell.

In a preferred embodiment, the inhibitor as above defined (a) is combined with at least one therapeutic agent (b) to define a combination or combined preparation. The therapeutic agent may be an anti-diabetic agent, an agent used to prevent diabetes, an anti-apoptotic agent, an anti-inflammatory agent, immune suppressive agent, adjuvant therapy in organ transplantation, protective agent in cell therapy approach a pain reliever.

Examples of therapeutic agent is insulin therapy, in any form, Pramlintide (Symlin), angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs), Aspirin, Cholesterol-lowering drugs. Metformin (Glucophage, Glumetza, others), Sulfonylureas (glyburide (DiaBeta, Glynase), glipizide (Glucotrol) and glimepiride (Amaryl), Meglitinides (for instance repaglinide (Prandin) and nateglinide (Starlix)), Thiazolidinediones (Rosiglitazone (Avandia) and pioglitazone (Actos) for examples), DPP-4 inhibitors (sitagliptin (Januvia), saxagliptin (Onglyza) and linagliptin (Tradjenta)), GLP-1 receptor agonists (Exenatide (Byetta) and liraglutide (Victoza)), SGLT2 inhibitors, examples include canagliflozin (Invokana) and dapagliflozin (Farxiga).

The terms “combination” and “combined preparation” as used herein also define a “kit of parts” in the sense that the combination partners (a) and (b) as defined above can be dosed independently or by use of different fixed combinations with distinguished amounts of the combination partners (a) and (b), i.e. simultaneously or at different time points. The parts of the kit of parts can then, e.g., be administered simultaneously or chronologically staggered, that is at different time points and with equal or different time intervals for any part of the kit of parts. The ratio of the total amounts of the combination partner (a) to the combination partner (b) to be administered in the combined preparation can be varied, e.g. in order to cope with the needs of a patient sub-population to be treated or the needs of the single.

The combination therapy may result in unexpected improvement in the treatment of diabetes. When administered simultaneously, sequentially or separately, the inhibitor and the other therapeutic agent may interact in a synergistic manner to reduce diabetes. This unexpected synergy allows a reduction in the dose required of each compound, leading to a reduction in the side effects and enhancement of the clinical effectiveness of the compounds and treatment. Determining a synergistic interaction between one or more components, the optimum range for the effect and absolute dose ranges of each component for the effect may be definitively measured by administration of the components over different w/w ratio ranges and doses to patients in need of treatment. For humans, the complexity and cost of carrying out clinical studies on patients renders impractical the use of this form of testing as a primary model for synergy. However, the observation of synergy in one species can be predictive of the effect in other species and animal models exist, as described herein, to measure a synergistic effect and the results of such studies can also be used to predict effective dose and plasma concentration ratio ranges and the absolute doses and plasma concentrations required in other species by the application of pharmacokinetic/pharmacodynamic methods. Established correlations between diabetes models and effects seen in man suggest that synergy in animals may e.g. be demonstrated in the models as described in the Examples below.

The above pharmaceutical compositions are preferably for systemic, oral, locally, preferably rectally, or topical administration.

Control amount is the amount measured in a proper control.

Control means can be used to compare the amount or the increase of amount of the compound as above defined to a proper control. The proper control may be obtained for example, with reference to known standard, either from a normal subject or from normal population.

The above diagnosis method may also comprise a step of treating the subject, in particular the treatment may be an inhibitor of IGFBP3/TMEM219 axis as defined in the present invention or an existing treatment for diabetes such as indicated above.

The means to measure the amount of IGFBP3 as above defined are preferably at least one antibody, functional analogous or derivatives thereof. Said antibody, functional analogous or derivatives thereof are specific for said compound.

In a preferred embodiment, the kit of the invention comprises:

-   -   a solid phase adhered antibody specific for said compound;     -   detection means of the ligand specific-biomarker complex.

The kits according to the invention can further comprise customary auxiliaries, such as buffers, carriers, markers, etc. and/or instructions for use.

The proper control may be a sample taken from a healthy patient or from a patient affected by a disorder other than diabetes.

In the case of a method or a kit for monitoring the progression of the diabetes, the progress of the disease is monitored and the proper control may be a sample taken from the same subject at various times or from another patient, and the proper control amount may by the amount of the same protein or polynucleotide measured in a sample taken from the same subject at various times or from another patient.

In the case of a method or a kit for monitoring the efficacy or response to a therapeutic treatment, the proper control may by a sample taken from the same subject before initiation of the therapy or taken at various times during the course of the therapy and the proper control amount may be the amount of the same protein or polynucleotide measured in a sample taken from the same subject before initiation of the therapy or taken at various times during the course of the therapy. The therapy may be the therapy with the inhibitor of the present invention.

In the present invention, the expression “measuring the amount” can be intended as measuring the amount or concentration or level of the respective protein and/or mRNA thereof and/or DNA thereof, preferably semi-quantitative or quantitative. Measurement of a protein can be performed directly or indirectly. Direct measurement refers to the amount or concentration measure of the biomarker, based on a signal obtained directly from the protein, and which is directly correlated with the number of protein molecules present in the sample. This signal—which can also be referred to as intensity signal—can be obtained, for example, by measuring an intensity value of a chemical or physical property of the biomarker. Indirect measurements include the measurement obtained from a secondary component (e.g., a different component from the gene expression product) and a biological measurement system (e.g. the measurement of cellular responses, ligands, “tags” or enzymatic reaction products).

The term “amount”, as used in the description refers but is not limited to the absolute or relative amount of proteins and/or mRNA thereof and/or DNA thereof, and any other value or parameter associated with the same or which may result from these. Such values or parameters comprise intensity values of the signal obtained from either physical or chemical properties of the protein, obtained by direct measurement, for example, intensity values in an immunoassay, mass spectroscopy or a nuclear magnetic resonance. Additionally, these values or parameters include those obtained by indirect measurement, for example, any of the measurement systems described herein. Methods of measuring mRNA and DNA in samples are known in the art. To measure nucleic acid levels, the cells in a test sample can be lysed, and the levels of mRNA in the lysates or in RNA purified or semi-purified from lysates can be measured by any variety of methods familiar to those in the art. Such methods include hybridization assays using detectably labeled DNA or RNA probes (i.e., Northern blotting) or quantitative or semi-quantitative RT-PCR methodologies using appropriate oligonucleotide primers. Alternatively, quantitative or semi-quantitative in situ hybridization assays can be carried out using, for example, tissue sections, or unlysed cell suspensions, and detectably labeled (e.g., fluorescent, or enzyme-labeled) DNA or RNA probes. Additional methods for quantifying mRNA include RNA protection assay (RPA), cDNA and oligonucleotide microarrays, representation difference analysis (RDA), differential display, EST sequence analysis, and serial analysis of gene expression (SAGE).

If by comparing the measured amount of the protein IGFBP3 or of the polynucleotide coding for said protein with the amount obtained from a control sample, the amount of said compound in the sample isolated from the subject corresponds to a higher value, the subject may present the disease or go towards an aggravation of said disease.

If by comparing the measured amount of the protein IGFBP3 or of the polynucleotide coding for said protein with the amount obtained from a control sample, the amount of said compound in the sample isolated from the subject corresponds to a similar or lower value, the subject may be not affected by the disease or go toward an amelioration of the disease, respectively.

Alternatively, the expression “detection” or “measuring the amount” is intended as measuring the alteration of the molecule. Said alteration can reflect an increase or a decrease in the amount of the compounds as above defined. An increase of the protein IGFBP3 or of the polynucleotide coding for said protein can be correlated to an aggravation of the disease. A decrease the protein IGFBP3 or of the polynucleotide coding for said protein can be correlated to an amelioration of the disease or to recovery of the subject.

The expression “protein IGFBP3” or “IGFBP3” or “TMEM219” is intended to include also the corresponding protein encoded from a IGFBP3 or TMEM orthologous or homologous genes, functional mutants, functional derivatives, functional fragments or analogues, isoforms thereof. The expression “gene IGFBP3” or “IGFBP3” or “gene TMEM219” or “TMEM219” is intended to include also the corresponding orthologous or homologous genes, functional mutants, functional derivatives, functional fragments or analogues, isoforms thereof.

In the present invention “functional mutants” of the protein are mutants that may be generated by mutating one or more amino acids in their sequences and that maintain their activity for the treatment of diabetes. Indeed, the protein of the invention, if required, can be modified in vitro and/or in vivo, for example by glycosylation, myristoylation, amidation, carboxylation or phosphorylation, and may be obtained, for example, by synthetic or recombinant techniques known in the art. The protein of the invention “IGFBP3” or “TMEM219” may be modified to increase its bioavailability or half-life by know method in the art. For instance the protein may be conjugated to a polymer, may be pegylated ect.

In the present invention the active ingredients may also be entrapped in microcapsule prepared, for example, by coacervation techniques or by interfacial polymerization, for example, hydroxymethylcellulose or gelatin-microcapsule and poly-(methylmethacylate) microcapsule, respectively, in colloidal drug delivery systems (for example, liposomes, albumin microspheres, microemulsions, nano-particles and nanocapsules) or in macroemulsions. Such techniques are disclosed in Remington's Pharmaceutical Sciences 16th edition, Osol, A. Ed. (1980).

The formulations to be used for in vivo administration must be sterile. This is readily accomplished by filtration through sterile filtration membranes.

Sustained-release preparations may be prepared. Suitable examples of sustained-release preparations include semipermeable matrices of solid hydrophobic polymers containing the antibody, which matrices are in the form of shaped articles, e.g., films, or microcapsule. Examples of sustained-releabe matrices include polyesters, hydrogels (for example, poly(2-hydroxyethyl-methacrylate), or poly(vinylalcohol)), polylactides (U.S. Pat. No. 3,773,919), copolymers of L-glutamic acid and [gamma] ethyl-L-glutamate, non-degradable ethylene-vinyl acetate, degradable lactic acid-glycolic acid copolymers such as injectable microspheres composed of lactic acid-glycolic acid copolymer and leuprolide acetate, and poly-D-(−)-3-hydroxybutyric acid. While polymers such as ethylene-vinyl acetate and lactic acid-glycolic acid enable release of molecules for over 100 days, certain hydrogels release proteins for shorter time periods. When encapsulated antibodies remain in the body for a long time, they may denature or aggregate as a result of exposure to moisture at 37° C., resulting in a loss of biological activity and possible changes in immunogenicity. Rational strategies can be devised for stabilization depending on the mechanism involved. For example, if the aggregation mechanism is discovered to be intermolecular S— S bond formation through thio-disulfide interchange, stabilization may be achieved by modifying sulfhydryl residues, lyophilizing from acidic solutions, controlling moisture content, using appropriate additives, and developing specific polymer matrix compositions.

In the present invention “functional” is intended for example as “maintaining their activity” e.g. therapeutic treatment of diabetes.

The term “analogue” as used herein referring to a protein means a modified peptide wherein one or more amino acid residues of the peptide have been substituted by other amino acid residues and/or wherein one or more amino acid residues have been deleted from the peptide and/or wherein one or more amino acid residues have been deleted from the peptide and or wherein one or more amino acid residues have been added to the peptide. Such addition or deletion of amino acid residues can take place at the N-terminal of the peptide and/or at the C-terminal of the peptide.

The term “derivative” as used herein in relation to a protein means a chemically modified peptide or an analogue thereof, wherein at least one substituent is not present in the unmodified peptide or an analogue thereof, i.e. a peptide which has been covalently modified. Typical modifications are amides, carbohydrates, alkyl groups, acyl groups, esters and the like. As used herein, the term “derivatives” also refers to longer or shorter polypeptides having e.g. a percentage of identity of at least 41%, preferably at least 41.5%, 50%, 54.9%, 60%, 61.2%, 64.1%, 65%, 70% or 75%, more preferably of at least 85%, as an example of at least 90%, and even more preferably of at least 95% with IGFBP3, or with an amino acid sequence of the correspondent region encoded from a IGFBP3 orthologous or homologous gene.

As used herein “fragments” refers to polypeptides having preferably a length of at least 10 amino acids, more preferably at least 15, at least 17 amino acids or at least 20 amino acids, even more preferably at least 25 amino acids or at least 37 or 40 amino acids, and more preferably of at least 50, or 100, or 150 or 200 or 250 or 300 or 350 or 400 or 450 or 500 amino acids. According to the present invention, an “effective amount” of a composition is one that is sufficient to achieve a desired biological effect, in this case an amelioration or the treatment of diabetes.

It is understood that the effective dosage will be dependent upon the age, sex, health, and weight of the recipient, kind of concurrent treatment, if any, frequency of treatment, and the nature of the effect desired. The provided ranges of effective doses of the inhibitor or molecule of the invention (e.g. from 1 mg/kg to 1000 mg/kg, in particular systemically administered) are not intended to limit the invention and represent preferred dose ranges. However, the preferred dosage can be tailored to the individual subject, as is understood and determinable by one of skill in the art, without undue experimentation.

The administration of oligonucleotides of the present invention may be carried out by known methods, wherein a nucleic acid is introduced into a desired target cell in vitro or in vivo.

An aspect of the present invention comprises a nucleic acid construct comprised within a delivery vehicle. A delivery vehicle is an entity whereby a nucleotide sequence can be transported from at least one media to another. Delivery vehicles may be generally used for expression of the sequences encoded within the nucleic acid construct and/or for the intracellular delivery of the construct. It is within the scope of the present invention that the delivery vehicle may be a vehicle selected from the group of RNA based vehicles, DNA based vehicles/vectors, lipid based vehicles, virally based vehicles and cell based vehicles. Examples of such delivery vehicles include: biodegradable polymer microspheres, lipid based formulations such as liposome carriers, coating the construct onto colloidal gold particles, lipopolysaccharides, polypeptides, polysaccharides, pegylation of viral vehicles.

In one embodiment of the present invention may comprise a virus as a delivery vehicle, where the virus may be selected from: adenoviruses, retroviruses, lentiviruses, adeno-associated viruses, herpesviruses, vaccinia viruses, foamy viruses, cytomegaloviruses, Semliki forest virus, poxviruses, RNA virus vector and DNA virus vector. Such viral vectors are well known in the art.

Commonly used gene transfer techniques include calcium phosphate, DEAE-dextran, transfection, electroporation and microinjection and viral methods. Another technique for the introduction of DNA into cells is the use of cationic liposomes. Commercially available cationic lipid formulations are e.g. Tfx 50 (Promega) or Lipofectamin 2000 (Life Technologies).

The compositions of the present invention may be in form of a solution, e.g. an injectable solution, a cream, ointment, tablet, suspension or the like. The composition may be administered in any suitable way, e.g. by injection, particularly by intraocular injection, by oral, topical, nasal, rectal application etc. The carrier may be any suitable pharmaceutical carrier. Preferably, a carrier is used, which is capable of increasing the efficacy of the RNA molecules to enter the target-cells. Suitable examples of such carriers are liposomes, particularly cationic liposomes.

The recombinant expression vector of the invention can be any suitable recombinant expression vector, and can be used to transform or transfect any suitable host. Suitable vectors include those designed for propagation and expansion or for expression or both, such as plasmids and viruses. The recombinant expression vectors of the invention can be prepared using standard recombinant DNA techniques. Constructs of expression vectors, which are circular or linear, can be prepared to contain a replication system functional in a prokaryotic or eukaryotic host cell. Replication systems can be derived, e.g., from CoIE1, 2μ plasmid, λ, SV40, bovine papilloma virus, and the like.

Desirably, the recombinant expression vector comprises regulatory sequences, such as transcription and translation initiation and termination codons, which are specific to the type of host (e.g., bacterium, fungus, plant, or animal) into which the vector is to be introduced, as appropriate and taking into consideration whether the vector is DNA- or RNA-based. The recombinant expression vector can include one or more marker genes, which allow for selection of transformed or transfected hosts. Marker genes include biocide resistance, e.g., resistance to antibiotics, heavy metals, etc., complementation in an auxotrophic host to provide prototrophy, and the like. Suitable marker genes for the inventive expression vectors include, for instance, neomycin/G418 resistance genes, hygromycin resistance genes, histidinol resistance genes, tetracycline resistance genes, and ampicillin resistance genes. The recombinant expression vector can comprise a native or normative promoter operably linked to the nucleotide sequence encoding the PCYOX1 inhibitor (including functional portions and functional variants thereof), or to the nucleotide sequence which is complementary to or which hybridizes to the nucleotide sequence encoding the RNA. The selection of promoters, e.g., strong, weak, inducible, tissue-specific and developmental-specific, is within the ordinary skill of the artisan. Similarly, the combining of a nucleotide sequence with a promoter is also within the skill of the artisan. The promoter can be a non-viral promoter or a viral promoter, e.g., a cytomegalovirus (CMV) promoter, an SV40 promoter, an RSV promoter and a promoter found in the long-terminal repeat of the murine stem cell virus.

The inventive recombinant expression vectors can be designed for either transient expression, for stable expression, or for both. Also, the recombinant expression vectors can be made for constitutive expression or for inducible expression.

In the above IGFBP3 compositions further materials as well as processing techniques and the like may be set out in Part 5 of Remington's Pharmaceutical Sciences, 20th Edition, 2000, Marck Publishing Company, Easton, Pa., which is incorporated herein by reference. The compounds of this invention can also be administered in sustained release forms or from sustained release drug delivery systems. A description of representative sustained release materials can also be found in the incorporated materials in Remington's Pharmaceutical Sciences. Furthermore, pharmaceutical formulations can be prepared using a process, which is generally known in the pharmaceutical art.

In the present invention, when the molecule of the invention is administered with another therapeutic agent, it may be administered simultaneously or sequentially.

Sequences Amino Acid Sequence of IGFBP3:

MQRARPTLWAAALTLLVLLRGPPVARAGASSAGLGPVVRCEPCDARALAQCAPPPAV CAELVREPGCGCCLTCALSEGQPCGIYTERCGSGLRCQPSPDEARPLQALLDGRGLCVN ASAVSRLRAYLLPAPPAPGEPPAPGNASESEEDRSAGSVESPSVSSTHRVSDPKFHPLHS KIIIIKKGHAKDSQRYKVDYESQSTDTQNFSSESKRETEYGPCRREMEDTLNHLKFLNVL SPRGVHIPNCDKKGFYKKKQCRPSKGRKRGFCWCVDKYGQPLPGYTTKGKEDVHCYS MQSK (SEQ ID No. 4)

Nucleotide Sequence of IGFBP3:

Homo sapiens insulin-like growth factor binding protein 3 (IGFBP3), RefSeqGene on chromosome 7, NCBI Reference Sequence: NG_011508.1

mRNA Sequence of IGFBP3:

Homo sapiens insulin-like growth factor binding protein 3 (IGFBP3), transcript variant 1, mRNA, NCBI Reference Sequence: NM_001013398.1

Amino Acid Sequence of TMEM219: MGNCQAGHNLHLCLAHHPPLVCATLILLLLGLSGLGLGSFLLTHRTGLRSPDIPQDWVS FLRSFGQLTLCPRNGTVTGKWRGSHVVGLLTTLNFGDGPDRNKTRTFQATVLGSQMGL KGSSAGQLVLITARVTTERTAGTCLYFSAVPGILPSSQPPISCSEEGAGNATLSPRMGEEC VSVWSHEGLVLTKLLTSEELALCGSRLLVLGSFLLLFCGLLCCVTAMCFHPRRESHWSR TRL (SEQ ID No. 2).

Nucleotide Sequence of TMEM219:

TMEM219 transmembrane protein 219 [Homo sapiens (human)], Gene ID: 124446.

mRNA Sequence of TMEM219:

Homo sapiens transmembrane protein 219 (TMEM219), transcript variant 1, mRNA, NCBI Reference Sequence: NM_001083613.1

The present invention will be illustrated by means of non limiting examples referring to the following figures.

FIG. 1. Diabetic enteropathy in long-standing T1D is characterized by intestinal mucosa abnormalities and impairment in the colonic stem cells. A, B, C. Bar graphs depict the score of diarrhea, abdominal pain and constipation according to the administration of the GSRS questionnaire in healthy subjects (CTRL) and long-standing T1D individuals (T1D+ESRD). Gray area indicates normal range for the parameter. D, E, F. Bar graphs report the measurements of anorectal sphincter contracting tone (mmHg), reflex response (ml) and urgency volume (ml) by anorectal manometry in healthy subjects (CTRL) and long-standing T1D individuals (T1D+ESRD). Gray area indicates normal range for the parameter. N=20 CTRL and n=60 T1D+ESRD individuals were included in the evaluation. G1-G2, I1-I2, K1-K2, M1-M2, O1-O2, Q1-Q2. Representative images of hematoxylin and eosin (H&E) histology staining, immunostained MIB1⁺ cells, ultrastructural analysis of neural structures with red arrows indicating localization and presence of neuroendocrine vesicles, immunostained 5HT⁺, aldehyde dehydrogenase (Aldh)⁺ cells, and EphB2⁺ expression, on bioptic samples obtained from healthy subjects (CTRL) and long-standing T1D individuals (T1D+ESRD). Ultrastructural analysis scale bar: 2000 nm. Original magnification: 100× in G1-G2; 400× in 11-12, K1-K2; 40× in O1-O2; 200×, in Q1-Q2. Scale bar 80 micron. H, J, L, N, P, R. Bar graphs reporting the measurement of crypts, MIB1⁺ cells, of neuroendocrine vesicles of nerve terminals (number of cases with >3 NE vesicles detected per nerve terminal), of 5HT⁺, Aldh⁺ cells, and of EphB2⁺ expression (intensity score 0-5) in CTRL and long-standing T1D subjects (T1D+ESRD). N=20 CTRL and n=60 T1D+ESRD individuals were included in the evaluation. Data are expressed as mean±standard error of the mean (SEM) unless differently reported. *p<0.01; **p<0.001; ***p<0.0001. Abbreviations: GSRS, Gastrointestinal Symptom Rating Scale; CoSC, intestinal stem cell; T1D, type 1 diabetes; ESRD, end stage renal disease; CTRL, healthy subjects; H&E, hematoxylin and eosin; MIB1, antibody against Ki67; EphB2, Ephrin B receptor 2; Aldh, Aldehyde dehydrogenase; 5HT, serotonin; NE, neuroendocrine vesicles.

FIG. 2. Diabetic enteropathy in long-standing T1D is associated with a defect in CoSCs. A, B. Representative flow dot plots of EphB2^(low), EphB2^(medium) and EphB2^(hi) cells in healthy subjects (CTRL) and long-standing T1D individuals (T1D+ESRD). C, D, E. Bar graphs depict results of flow cytometric analysis of EphB2^(hi+), EphB2^(hi+)LGR5⁺ and EphB2⁺h-TERT⁺ cells in freshly isolated crypts (n=10 CTRL and n=10 T1D+ESRD). F, G, H. Bar graphs depict expression data of CoSC markers EphB2, LGR5, h-TERT as normalized mRNA expression measured by quantitative RT-PCR on isolated intestinal crypts. All samples were run in triplicate and normalized to expression of the housekeeping gene ACTB (ΔΔCt). I. Scatter plot represents the CoSC signature markers and stem cell transcriptome profiling examined in freshly isolated intestinal crypts of n=10 healthy subjects (CTRL) and n=10 long-standing T1D individuals (T1D+ESRD). J1-J2. Representative images of mini-guts cultured for 8 days in vitro obtained from previously isolated crypts of long-standing T1D individuals (T1D+ESRD) and healthy subjects (CTRL). 10× magnification. Scale bar 50 micron. K. Bar graph depicts the % of developed mini-guts of the total at 8 days of culture of freshly isolated intestinal crypts from n=10 CTRL and n=10 T1D+ESRD individuals. L1-L4. Representative images of mini-guts obtained from previously isolated crypts of healthy subjects (CTRL) and cultured for 8 days in the following conditions: L1=normal (FBS) serum+normal glucose (5 mM); L2=T1D+ESRD serum+normal glucose; L3=normal serum+high glucose (35 mM); L4=T1D+ESRD serum+high glucose. 10× magnification. Scale bar 50 micron. M. Bar graph grouping % of developed mini-guts of the total at 8 days of culture from freshly isolated intestinal crypts cultured with the following conditions: normal (FBS) serum+normal glucose (5 mM); T1D+ESRD serum+normal glucose; normal serum+high glucose (35 mM); T1D+ESRD serum+high glucose. Statistical significance has been calculated within each group (normal glucose+normal serum, medium+high glucose, medium+long-standing T1D serum, high glucose+long-standing T1D serum) by comparing different culturing conditions. Comparison in the bar graph refers to all conditions vs. normal serum+normal glucose. N. Transcriptome profiling depicting CoSC signature markers expression in isolated crypts obtained from healthy subjects and cultured with/without high glucose and/or long-standing T1D serum. N=10 subjects per group were evaluated. Data are expressed as mean±standard error of the mean (SEM) unless differently reported. *p<0.01; **p<0.001; ***p<0.0001. Abbreviations: CoSC, colonic stem cell; T1D, type 1 diabetes; ESRD, end stage renal disease; CTRL, healthy subjects; EphB2, Ephrin B receptor 2; LGR5, leucine-rich repeat containing G protein-coupled receptor 5; RT-PCR, real-time polymerase chain reaction; ACTB, beta actin; FBS, fetal bovine serum.

FIG. 3. Circulating IGF-I and IGFBP3 are altered in long-standing T1D and its manipulation in vitro induces profound effects on CoSC growth and self-renewal. A. Heat map represents the proteomic profile in long-standing T1D (T1D+ESRD) as compared to healthy subjects (CTRL). The complete dataset of identified and quantified proteins was subjected to statistical analysis (p<0.01). Significantly differentially expressed proteins were further analyzed through hierarchical clustering. Sera of n=10 CTRL and n=10 T1D+ESRD individuals were analyzed. B. Bar graph depicts LFQ intensity for a single protein extrapolated from the untargeted proteomic analysis, insulin-like growth factor binding protein 3 (IGFBP3). C1-C2. Representative images (40× magnification) of IGFBP3 expression in the liver. IGFBP3 is mildly and diffusely expressed in the liver parenchyma from healthy subjects (C1), while it is more zonally positive in long-standing diabetic individuals (C2). D. Bar graph represents IGFBP3 levels measured by ELISA in the supernatants of immortalized human hepatoma cell line (HuH-7) cultured for 5 days at different glucose concentrations (35 mM: high glucose; 20 mM: intermediate glucose; 5 mM: normal glucose). Experiments were run in triplicate. E. Bar graph represents insulin-like growth factor 1 (IGF-I) levels measured by ELISA in serum of healthy subjects and long-standing T1D (T1D+ESRD). F. Western blot analysis (cropped blots) confirmed IGF-IR and TMEM219 expression on the intestinal crypt surface. Evaluation of total IGF-IR expression by WB includes the detection of IGF-IRu, a subunit of IGF-IR whole protein. Representative pictures of TMEM219 in situ hybridization (G1 negative control, G2 TMEM219 staining) performed on rectal mucosa biopsy samples obtained from CTRL. 20× magnification. G1-G2. Representative pictures of TMEM219 in situ hybridization (G1 negative control, G2 TMEM219 staining) performed on rectal mucosa biopsy samples obtained from CTRL. Magnification 400×. H. Bar graph depicts normalized mRNA expression of TMEM219 (IGFBP3 receptor) using the ΔΔCt method. N=5 subjects per group were evaluated. I. Bar graph grouping % of developed mini-guts of the total obtained from long-standing T1D individuals in different conditions and showing the effect of IGF-I, IGFBP3 and anti-IGF-IR. The p values are relative to baseline conditions and addition of IGF-I to culture. J. Bar graph representing normalized mRNA expression of Caspase 8 and 9 in crypts isolated from healthy subjects cultured in the presence of IGFBP3 and IGF-I+IGFBP3, performed in triplicate. K. Bar graph grouping % of developed mini-guts of the total at 8 days of culture, obtained from healthy subjects and cultured in the presence of a Pan-Caspase inhibitor, selective inhibitors of Caspase 8, 9 and 3, and IGFBP3. Assay was performed in triplicate. L. Bar graphs grouping % of developed mini-guts of the total obtained from healthy subjects and cultured in different conditions (normal glucose+normal serum, high glucose+normal serum, T1D+ESRD serum+normal glucose, T1D+ESRD serum+high glucose) and showing the effect of IGF-I, IGFBP3 and anti-IGF-IR. The p values are relative to baseline condition (medium alone, medium+high glucose, medium+long-standing T1D serum, high glucose+long-standing T1D serum). Additional p values have been calculated to compare the difference in mini-gut growth among the following conditions: medium alone vs. medium+high glucose, vs. medium+high glucose+long-standing T1D serum). Assay was performed in triplicate. M. Bar graph grouping % of developed mini-guts of the total obtained from healthy subjects, cultured for 8 days, exposed to TMEM219 targeting with siRNA and finally compared to TMEM219-expressing crypts in medium alone and in medium+high glucose+long-standing T1D serum. Assay was performed in triplicate. Data are expressed as mean±standard error of the mean (SEM) unless differently reported. *p<0.01; **p<0.001; ***p<0.0001. Abbreviations: IGF-I, insulin-like growth factor 1; IGFBP3, insulin-like growth factor binding protein 3; IGF-IR, insulin-like growth factor 1 receptor; CoSC, colonic stem cell; T1D, type 1 diabetes; ESRD, end stage renal disease; CTRL, healthy subjects; RT-PCR, real-time polymerase chain reaction; ACTB, beta actin; LFQ, Label-free quantitation; SEM, standard error of the mean; siRNA, small RNA interference; inhib, inhibitor.

FIG. 4. Effects of the peripheral IGF-I/IGFBP3 dyad on single-cell derived in vitro mini-guts and on caspase cascade. Manipulating the peripheral IGF-I/IGFBP3 dyad alters the progression of diabetic enteropathy in a preclinical model of diabetic enteropathy, while the treatment of long-standing T1D with simultaneous pancreas-kidney transplantation (SPK) ameliorates intestinal symptoms, motility and morphology. A. Bar graph representing normalized mRNA expression of TMEM219, LRP1, TGF-β type I and II, in EphB2⁺ sorted single cells obtained from crypts of healthy subjects. Experiments were performed in triplicate. B. Bar graphs showing % of developed single cell-derived mini-guts (of the total) obtained from EphB2⁺ cells sorted from freshly isolated crypts of healthy subjects and cultured in different conditions (normal glucose+normal serum, high glucose+normal serum, T1D+ESRD serum+normal glucose, T1D+ESRD serum+high glucose) and showing the effect of IGF-I and IGFBP3. The p values are relative to baseline condition. C, D. Scatter plot representing the apoptosis transcriptome profiling examined in freshly isolated intestinal crypts of healthy subjects (CTRL) and long-standing T1D individuals (T1D+ESRD) cultured with/without IGFBP3 and IGF-I. Experiments were run in triplicate. E. Schematic attempt to represent the effect of circulating IGF-I and IGFBP3 on the CoSCs. F, G, I. Line graphs reporting the number of crypts (B), depth of crypts (C) and width of crypts (E) assessed on intestinal lower tract sections harvested at baseline and after 8 weeks from STZ-treated B6 mice developing diabetic enteropathy (B6+STZ), naïve B6 (WT), and naïve B6 treated with IGFBP3 (WT+IGFBP3). WT: wild type, STZ: streptozoticin-treated. N=3 mice per group were evaluated. H1-H3. Representative images of intestinal crypts on H&E sections of WT, B6+STZ mice developing diabetic enteropathy, and naïve B6 treated with IGFBP3 (WT+IGFBP3). Histology magnification, 400×. J. Bar graph representing the number of Aldh⁺ cells/mm² in immunostained sections of STZ-treated B6 mice developing diabetic enteropathy, WT, and naïve B6 treated with IGFBP3 (WT+IGFBP3). K1-K3. Representative images of Aldh⁺ cells on immunostained sections of intestinal lower tract harvested from STZ-treated B6 mice developing diabetic enteropathy, WT, and naïve B6 treated with IGFBP3 (WT+IGFBP3). Histology magnification, 400×. L, N, P. Bar graphs report the measurement of MIB1⁺ and Aldh⁺ cells, and EphB2⁺ expression (intensity score 0-5) in the four groups of subjects (n=20 CTRL, n=30 SPK, n=K+T1D and n=60 T1D+ESRD). M1-M2, O1-O2, Q1-Q2. Representative images of MIB1⁺ and Aldh⁺ cells, and EphB2⁺ expression in immunostained rectal mucosa bioptic samples of T1D+ESRD who underwent kidney alone (K+T1D) or simultaneous pancreas-kidney (SPK) transplantation at 8 years of follow-up. Histology 400× in M1-M2 and O1-O2, 20× in Q1-Q2. Scale bar 80 micron. Data are expressed as mean±standard error of the mean (SEM) unless differently reported. *p<0.01; **p<0.001; ***p<0.0001. Abbreviations: WT, wild type; STZ, streptozoticin-treated; B6, C57BL/6J mice; IGF-I, insulin-like growth factor 1; IGFBP3, insulin-like growth factor binding protein 3; IGF-IR, insulin-like growth factor 1 receptor; CoSC, colonic stem cell; T1D, type 1 diabetes; ESRD, end stage renal disease; CTRL, healthy subjects; SPK, simultaneous kidney-pancreas transplantation; K+T1D, kidney transplantation alone in type 1 diabetes; H&E, hematoxylin and eosin; MIB1, antibody against Ki67; EphB2, Ephrin B receptor 2; Aldh, Aldehyde dehydrogenase; SEM, standard error of the mean.

FIG. 5. Treatment of long-standing T1D with SPK replenishes CoSCs and restores the CoSC signature profile and mini-gut development through restoration of circulating IGF-I and IGFBP3. A, B, C. Bar graphs depict results of flow cytometric analysis of EphB2^(hi+), EphB2^(hi+)LGR5⁺, EphB2⁺h-TERT⁺ cells obtained from isolated crypts in long-standing T1D (Baseline), T1D+ESRD who underwent kidney pancreas (SPK) or kidney alone (K+T1D) transplantation at 8 years of follow-up. N=10 subjects per group were evaluated. D, E, F. Bar graphs depict normalized mRNA expression of intestinal stem cell markers EphB2, LGR5, h-TERT, measured by quantitative RT-PCR on isolated intestinal crypts obtained from long-standing T1D (Baseline), T1D+ESRD who underwent kidney pancreas (SPK) or kidney alone (K+T1D) transplantation at 8 years of follow-up. All samples were run in triplicate and normalized to expression of the housekeeping gene ACTB using the ΔΔCt method. N=10 subjects per group were evaluated. G. Western blot analysis depicts the expression of EphB2, LGR5, h-TERT in isolated intestinal crypts of the four groups at 8 years of follow-up. N=5 subjects per group were evaluated. H. Bar graph depicts the % of developed mini-guts of the total at 8 days of culture of freshly isolated intestinal crypts obtained from long-standing T1D individuals (Baseline), SPK and K+T1D subjects at 8 years of follow-up. N=10 subjects per group were evaluated. I. Heat map represents the CoSC signature marker transcriptomic profiling examined in freshly isolated intestinal crypts of CTRL, long-standing T1D individuals (T1D+ESRD), SPK and K+T1D subjects at 8 years of follow-up. N=10 subjects per group were evaluated. J. Bar graph represents IGF-I levels measured by ELISA in serum of the four groups of subjects at 8 years of follow-up. N=10 subjects per group were evaluated. K. Bar graph depicts IGFBP3 levels measured by ELISA in serum of the four groups of subjects. N=20 subjects per group were evaluated. L, M Correlation between IGFBP3 serum levels and intestinal symptoms assessed using the GSRS questionnaire (0-7) in n=20 subjects of K+T1D (L) and SPK (M) group. Analysis was conducted using ANOVA (p<0.05) in comparing all groups. Data are expressed as mean±standard error of the mean (SEM) unless differently reported. *p<0.01; **p<0.001; ***p<0.0001. Abbreviations: CoSC, colonic stem cell; T1D, type 1 diabetes; ESRD, end stage renal disease; CTRL, healthy subjects; SPK, simultaneous kidney-pancreas transplantation; EphB2, Ephrin B receptor 2; LGR5, leucine-rich repeat containing G protein-coupled receptor 5; RT-PCR, real-time polymerase chain reaction; ACTB, beta actin; K+T1D, kidney transplantation alone in type 1 diabetes; IGF-I, insulin-like growth factor 1; IGFBP3, insulin-like growth factor binding protein 3; SEM, standard error of the mean.

FIG. 6. Treatment with the newly generated recombinant protein ecto-TMEM219 (ecto-TMEM219) abrogates IGFBP3-mediated mini-gut destruction and preserves CoSCs in preclinical model. A. Bar graph grouping % of developed mini-guts of the total obtained from healthy subjects in different conditions and showing the effect of ecto-TMEM219 at various concentrations (1:2, 1:1 and 2:1 molar ratio as compared to IGFBP3) in IGFBP3-treated mini-guts and in those exposed to high glucose. The p values are relative to baseline conditions. B. Bar graph representing normalized mRNA expression of EphB2 in crypts isolated from healthy subjects cultured in the presence of IGFBP3 and ecto-TMEM219+IGFBP3, performed in triplicate. C. D. Bar graph representing normalized mRNA expression of Caspase 8 and 9 in crypts isolated from healthy subjects cultured in the presence of IGFBP3 and ecto-TMEM219+IGFBP3, performed in triplicate. E, F, G. Line graphs reporting the number of crypts (E), depth of crypts (F) and width of crypts (G) assessed on intestinal lower tract sections harvested at baseline and after 8 weeks from STZ-treated B6 mice developing diabetic enteropathy (B6+STZ), naïve B6 (WT), and STZ-B6 mice treated with ecto-TMEM219. WT: wild type, STZ: streptozoticin-treated. N=3 mice per group were evaluated. H. Line graph reporting the weight at baseline and after 8 weeks of STZ-treated B6 mice developing diabetic enteropathy (B6+STZ), naïve B6 (WT), and of STZ-treated B6 mice developing diabetic enteropathy treated with ecto-TMEM219. WT: wild type, STZ: streptozoticin-treated. N=3 mice per group were evaluated. I. Bar graph representing results of flow cytometric analysis of EphB2⁺ cells isolated from intestinal samples collected from naïve B6 mice, STZ-treated B6 mice and in STZ-B6 mice treated with ecto-TMEM219 at 8 weeks. J. Representative flow histograms of EphB2⁺ cells isolated from crypts isolated from naïve B6 mice, STZ-treated B6 mice and in STZ-B6 mice treated with ecto-TMEM219 at 8 weeks. N=3 to 5 mice per group were evaluated. K. Bar graph representing normalized mRNA expression of EphB2 in intestinal samples collected from naïve B6 mice, STZ-treated B6 mice and in STZ-B6 mice treated with ecto-TMEM219 at 8 weeks. L, M. Bar graph representing normalized mRNA expression of Caspase 8 (K) and Caspase 9 (L) in intestinal samples collected from naïve B6 mice, STZ-treated B6 mice and in STZ-B6 mice treated with ecto-TMEM219 at 8 weeks. N. Bar graph representing IGFBP3 circulating levels measured in naïve B6 mice (WT) and STZ-treated B6 mice (B6+STZ) and in B6+STZ mice treated with ecto-TMEM219 at 8 weeks. Data are expressed as mean±standard error of the mean (SEM) unless differently reported. *p<0.01; **p<0.001; ***p<0.0001. Abbreviations: WT, wild type; STZ, streptozoticin-treated; B6, C57BL/6J mice; IGF-I, insulin-like growth factor 1; IGFBP3, insulin-like growth factor binding protein 3; CoSC, colonic stem cell; H&E, hematoxylin and eosin; EphB2, Ephrin B receptor 2; SEM, standard error of the mean, T1D, type 1 diabetes; ESRD, end stage renal disease; CTRL, healthy subjects; RT-PCR, real-time polymerase chain reaction; ACTB, beta actin.

FIG. 7. Assessment of IGFBP3 levels in serum (A) and urine (B) of CTRL, T1D and T1D+ESRD individuals. (C) Correlation between serum and urine IGFBP3 levels in all subjects of the cohort evaluated for this study. (D-E) Correlation between IGFBP3 serum levels and eGFR calculated with MDRD formula in subjects with T1D+ESRD on dialysis (D) and with T1D with eGFR>15 ml/min/m2 (E). (F) Correlation between serum and urine IGFBP3 levels in all subjects of the cohort evaluated for this study. The gray area indicates the normal range within urinary and serum levels of IGFBP3.

FIG. 8. CoSC profile, in vitro generation of mini-guts, expression of IGFBP3 in the liver and of IGF-IR on CoSCs in long-standing T1D and healthy subjects. A-B. Representative flow dot plots of PI⁻ cells gating strategy in healthy subjects (CTRL) and long-standing T1D individuals (T1D+ESRD). C. Bar graphs depict results of flow cytometric analysis of PI⁻ cells in freshly isolated crypts (n=10 CTRL and n=10 T1D+ESRD). D-E. Representative flow dot plots of EphB2^(hi)LGR5⁺ (D) and EphB2⁺h-TERT⁺ cells in healthy subjects (CTRL) and long-standing T1D individuals (T1D+ESRD). F. Western blot analysis (cropped blots) confirms low expression of EphB2, LGR5, h-TERT in in vitro isolated intestinal crypts of long-standing T1D individuals (T1D+ESRD). Full-length blots are presented in FIG. 5. N=5 subjects per group were evaluated. G. Scatter plot representing the stem cell transcriptome profiling examined in freshly isolated intestinal crypts of healthy subjects (CTRL) and long-standing T1D individuals (T1D+ESRD). A table summarizes genes and pathways analyzed (Table S1). N=10 subjects per group were evaluated. H-I. Representative images of freshly isolated crypts obtained from healthy subjects and long-standing T1D individuals stained with DAPI. 20× magnification. J. Bar graph representing percentage of mini-guts forming efficiency of plated crypts obtained from healthy subjects and long-standing T1D individuals at 12 hours. N=10 subjects per group were evaluated. K. Bar graph representing the calculated combined score of IGFBP3 intensity/diffusion (0-6) upon immunohistochemical evaluation in liver samples obtained from healthy subjects and long-standing T1D individuals. N=3 subjects per group were evaluated. L1-L6. Representative images (63× magnification) of IGFBP3 expression in the liver. Immunofluorescence confirmed the colocalization of Hep Par-1⁺ cells and IGFBP3 expression (L1-L3), while no colocalization was observed between IGFBP3 and CD163⁺ cells (L4-L6). M. Bar graph depicts normalized mRNA expression of the IGF-I receptor (IGF-IR) measured by quantitative RT-PCR on isolated intestinal crypts. All samples were run in triplicate and normalized to the housekeeping gene ACTB using the ΔΔCt method. N1-N2. Representative pictures of IGF-IR⁺ cells on rectal mucosa samples obtained from CTRL and from T1D+ESRD individuals. Black arrow indicates positive cells at the crypt base. Magnification 200×. O1-O2. Representative pictures of TMEM219 in situ hybridization performed on rectal mucosa biopsy samples obtained from CTRL and from T1D+ESRD individuals. Magnification 400×. Data are expressed as mean±standard error of the mean (SEM) unless differently reported. *p<0.01. Abbreviations: PI, propidium iodide; IGF-I, insulin-like growth factor 1; IGFBP3, insulin-like growth factor binding protein 3; IGF-IR, insulin-like growth factor 1 receptor; CoSC, colonic stem cell; T1D, type 1 diabetes; ESRD, end stage renal disease; CTRL, healthy subjects; EphB2, Ephrin B receptor 2; LGR5, leucine-rich repeat containing G protein-coupled receptor 5; RT-PCR, real-time polymerase chain reaction; ACTB, beta actin; SEM, standard error of the mean.

FIG. 9. Caspases expression in IGF-I/IGFBP3 cultured mini-guts and the lack of effect of other circulating factors confirmed IGFBP3 major pro-apoptotic effect on mini-guts development. A. Bar graph representing normalized mRNA expression of Caspase 8 in crypts isolated from individuals with T1D+ESRD cultured in the presence of IGFBP3, IGF-I+IGFBP3 and IGF-I, performed in triplicate. B. Bar graph representing normalized mRNA expression of Caspase 9 in crypts isolated from individuals with T1D+ESRD cultured in the presence of IGFBP3, IGF-I+IGFBP3 and IGF-I, performed in triplicate. C, D. Bar graph grouping % of mini-guts developed from healthy subjects (C) and from long-standing T1D individuals (D), cultured in the presence of medium with FBS and medium with serum obtained from healthy subjects, “CTRL serum”. Assay was run in triplicate. E. Bar graph grouping % of developed mini-guts of the total obtained from healthy subjects, cultured for 8 days, exposed to TMEM219 targeting with siRNA and anti-IGF-IR, and finally compared to TMEM219-expressing crypts in medium alone and in medium+high glucose+long-standing T1D serum. Assay was performed in triplicate. F, G. Bar graph grouping % of developed mini-guts at 8 days of culture, obtained from healthy subjects (F) and long-standing T1D individuals (G) cultured in the presence of medium alone and various molecules identified with proteomic analysis (Table S7). Assay was performed in triplicate. H. Bar graph grouping % of mini-guts obtained from healthy subjects and cultured in the presence of medium alone, medium+high glucose, medium+high glucose and long-standing T1D serum, IGF-I, IGFBP3 with/without insulin. Assay was performed in triplicate. Data are expressed as mean±standard error of the mean (SEM) unless differently reported. *p<0.01; **p<0.001. Abbreviations: IGF-I, insulin-like growth factor 1; IGFBP3, insulin-like growth factor binding protein 3; IGF-IR, insulin-like growth factor 1 receptor; CoSC, colonic stem cell; T1D, type 1 diabetes; ESRD, end stage renal disease; CTRL, healthy subjects; RT-PCR, real-time polymerase chain reaction; ACTB, beta actin; SEM, standard error of the mean; siRNA, small RNA interference; ALDOA, Fructose-bisphosphate aldolase A; RNASE, Ribonuclease pancreatic; MASP, Mannan-binding lectin serine protease 1.

FIG. 10. Effect of IGF-I/IGFBP3 dyad on single cell derived mini-guts, on stem cell transcriptome profile and on apoptotic pathways. A1-A3. Representative images of single cell-derived mini-guts, cultured for 8 days in vitro obtained from previously isolated EphB2⁺ sorted cells of healthy subjects and cultured with medium alone, medium+IGFBP3, medium+Glucose 35 mM+long-standing T1D serum. Images are shown at 10× magnification. Scale bar 50 micron. B, C, D. Bar graph representing normalized mRNA expression of Caspase 8, Caspse 9 and Ki67 in single cell-derived mini-guts grown from flow sorted EphB2⁺ cells isolated from healthy subjects and cultured in different conditions. Assay was performed in triplicate. E, F. Scatter plot representing the stem cell transcriptome profiling examined in freshly isolated intestinal crypts of healthy subjects (CTRL) and long-standing T1D individuals (T1D+ESRD) cultured with/without IGFBP3 and IGF-I. Assays were run in triplicate. G, H. Scatter plot representing the apoptosis transcriptome profiling examined in freshly isolated intestinal crypts of healthy subjects (CTRL) and long-standing T1D individuals (T1D+ESRD) cultured with/without IGF-I. A table summarizes genes and pathways analyzed (Table S3). Assays were run in triplicate. I, J. Bar graph grouping % of mini-guts developed from crypts obtained from healthy subjects (I) and long-standing T1D (J) and then cultured in the presence of medium alone, Fas Ligand (FasL), hydrogen peroxide (H₂O₂) and Tumor Necrosis Factor alpha (TNF-α). Assay was performed in triplicate. Data are expressed as mean±standard error of the mean (SEM) unless differently reported. *p<0.01; **p<0.001; ***p<0.0001. Abbreviations: IGF-I, insulin-like growth factor 1; IGFBP3, insulin-like growth factor binding protein 3; CoSC, colonic stem cell; T1D, type 1 diabetes; ESRD, end stage renal disease; CTRL, healthy subjects; RT-PCR, real-time polymerase chain reaction; ACTB, beta actin; SEM, standard error of the mean; FasL, Fas Ligand; H₂O₂, hydrogen peroxide; TNF-α, Tumor Necrosis Factor alpha.

FIG. 11. Manipulating IGF-I/IGFBP3 dyad in preclinical models of diabetic enteropathy. A. Bar graph representing IGFPB3 circulating levels measured in naïve B6 mice (WT) and STZ-treated B6 mice (B6+STZ). B. Bar graph representing IGF-I circulating levels measured in naïve B6 mice (WT) and STZ-treated B6 mice (B6+STZ). C. Bar graph representing insulin serum levels measured in naïve B6 mice (WT) and STZ-treated B6 mice (B6+STZ). D, E, F: Line graphs reporting the number of crypts (D), depth of crypts (E) and width of crypts (F) assessed on intestinal lower tract sections harvested at baseline and after 8 weeks from STZ-treated B6 mice developing diabetic enteropathy (B6+STZ), naïve B6 (WT), and STZ-B6 mice treated with IGFBP3 (B6+STZ+IGFBP3) or with IGF-I (B6+STZ+IGF-I). WT: wild type, STZ: streptozoticin-treated. N=3 mice per group were evaluated. G. Bar graph representing the number of Aldh⁺ cells/mm² in immunostained sections of STZ-treated B6 mice developing diabetic enteropathy, WT, and STZ-B6 mice treated with IGFBP3 (B6+STZ+IGFBP3) or with IGF-I (B6+STZ+IGF-I). H1-H2: Representative images of intestinal crypts on H&E sections of STZ-B6 mice treated with IGFBP3 (B6+STZ+IGFBP3), (H1) or with IGF-I (B6+STZ+IGF-I), (H2). Histology magnification, 400×. I. Line graph reporting the weight of STZ-treated B6 mice developing diabetic enteropathy (B6+STZ), naïve B6 (WT), STZ-treated B6 mice developing diabetic enteropathy treated with IGFBP3 (B6+STZ+IGFBP3). WT: wild type, STZ: streptozoticin-treated. N=3 mice per group were evaluated. J. Bar graph representing results of flow cytometric analysis of EphB2⁺ cells in intestinal samples collected from naïve B6 mice, STZ-treated B6 mice and in STZ-B6 mice treated with IGFBP3 (B6+STZ+IGFBP3). K, L. Bar graph representing normalized mRNA expression of EphB2 (K) and LGR5 (L) in intestinal samples collected from naïve B6 mice, STZ-treated B6 mice and in STZ-B6 mice treated with IGFBP3 (B6+STZ+IGFBP3). M, N. Bar graph representing normalized mRNA expression of Caspase 8 (M) and Caspase 9 (N) in intestinal samples collected from naïve B6 mice, STZ-treated B6 mice and in STZ-B6 mice treated with IGFBP3 (B6+STZ+IGFBP3). Data are expressed as mean±standard error of the mean (SEM) unless differently reported. *p<0.01; **p<0.001; ***p<0.0001. Abbreviations: WT, wild type; STZ, streptozoticin-treated; B6, C57BL/6J mice; IGF-I, insulin-like growth factor 1; IGFBP3, insulin-like growth factor binding protein 3; CoSC, colonic stem cell; H&E, hematoxylin and eosin; EphB2, Ephrin B receptor 2; Aldh, Aldehyde dehydrogenase; SEM, standard error of the mean.

FIG. 12. The treatment of long-standing T1D with SPK ameliorates diabetic enteropathy. A, B, C. Bar graphs depict the score of abdominal pain, diarrhea and constipation according to the GSRS questionnaire in healthy subjects (CTRL), long-standing T1D individuals (Baseline), T1D+ESRD who underwent kidney pancreas (SPK) or kidney alone (K+T1D) transplantation. Gray area indicates normal range for all the parameters. Statistics are expressed as mean±SEM. D1-D2, E1-E2, G1-G2, J1-J2. Representative pictures of hematoxylin and eosin (H&E) staining and ultrastructural analysis of neural structures (red arrows indicate localization and presence of neuroendocrine vesicles), Schwann cells (red arrows indicate cytoplasm derangements), and 5HT⁺ cells performed on rectal mucosa biopsy samples obtained from T1D+ESRD who underwent kidney pancreas (SPK) or kidney alone (K+T1D) transplantation at 8 years of follow-up. Magnification 400×. F, H, I, K. Bar graphs report the measurements of neuroendocrine vesicles (% of cases with >3 NE vesicles detected per nerve terminal), % of Schwann cells with picnotic nuclei and cytoplasm derangements (% of positive cases) using electron microscopy, 5HT⁺ cells, performed on bioptic samples obtained from rectal mucosa of CTRL, long-standing T1D individuals (Baseline), T1D+ESRD who underwent kidney pancreas (SPK) or kidney alone (K+T1D) over an 8-year follow-up period. Statistics are expressed as mean±SEM. N=20 CTRL, n=30 SPK, n=30 K+T1D and n=60 T1D+ESRD subjects were evaluated. Statistics are expressed as mean±SEM. All parameters examined were statistically significantly different when comparing different groups as following: *p<0.01; **p<0.001; ***p<0.0001. N=10 subjects per group were evaluated. Abbreviations: GSRS, Gastrointestinal Symptom Rating Scale; SPK, simultaneous kidney-pancreas transplantation; K+T1D, kidney transplantation alone in type 1 diabetes; CTRL, healthy subjects; T1D, type 1 diabetes; ESRD, end stage renal disease; 5HT, serotonin; H&E, hematoxylin and eosin; NGF, neural growth factor; SEM, standard error of the mean; NE, neuroendocrine vesicles.

FIG. 13. Analysis of colonic stem cells, IGF-IR and proteomic profile of circulating factors in diabetic enteropathy in SPK and K+T1D groups. A1-A6. Representative images of mini-guts, cultured for 8 days in vitro obtained from previously isolated crypts of long-standing T1D individuals, T1D+ESRD who underwent kidney pancreas (SPK) or kidney alone (K+T1D) transplantation at 8 years of follow-up. Images are shown at 5× and 10× magnification. Scale bar 10 micron. B. Scatter plot representing the stem cell transcriptome profiling examined in freshly isolated intestinal crypts of SPK individuals. N=3 subjects were evaluated. C. Bar graphs depict relative expression levels of IGF-I receptor (IGF-IR) on isolated crypts of healthy subjects (CTRL), long-standing T1D individuals (T1D+ESRD), SPK and K+T1D measured by quantitative RT-PCR. All samples were run in triplicate and normalized to the ACTB relative expression level using the ΔΔCt method. Results are expressed as mean±SEM. D. Heat map represents the proteomic profile of long-standing T1D as compared to CTRL and SPK subjects at 8 years of follow-up. The complete dataset of identified and quantified proteins was subjected to statistical analysis (p<0.05). Significantly differentially expressed proteins were further analyzed through hierarchical clustering. Statistics are expressed as mean±SEM. Sera of n=10 subjects per group were evaluated. All parameters examined were statistically significantly different when comparing different groups as following: *p<0.01. Abbreviations: T1D, type 1 diabetes; ESRD, end stage renal disease; CTRL, healthy subjects; SPK, simultaneous kidney-pancreas transplantation; K+T1D, kidney transplantation alone in type 1 diabetes; RT-PCR, real-time polymerase chain reaction; ACTB, beta actin; IGF-I, insulin-like growth factor 1; IGFBP3, insulin-like growth factor binding protein 3; IGF-IR, insulin-like growth factor 1 receptor; SEM, standard error of mean.

FIG. 14. Correlation of intestinal symptoms with levels of insulin, HbA1C and blood glucose in SPK and K+T1D groups. A, B. Correlation between insulin serum levels and intestinal symptoms assessed using the GSRS questionnaire and considering the item with the highest score (0-7) in n=20 subjects of K+T1D (A) and SPK (B) group. Analysis was conducted using ANOVA (p<0.05) in comparing all groups. C. Insulin serum levels measured using the Free-insulin method in n=20 subjects of K+T1D (A) and SPK (B) group. Data are expressed as mean±standard error of the mean (SEM). D, E. Correlation between glycated hemoglobin (HbA1C) serum levels and intestinal symptoms assessed using the GSRS questionnaire (0-7) in n=20 subjects of K+T1D (A) and SPK (B) group. Analysis was conducted using ANOVA (p<0.05) in comparing all groups. F, G. Correlation between blood glucose levels (Glycemia) and intestinal symptoms assessed using the GSRS questionnaire (0-7) in n=20 subjects of K+T1D (A) and SPK (B) group. Analysis was conducted using ANOVA (p<0.05) in comparing all groups. Abbreviations: T1D, type 1 diabetes; ESRD, end stage renal disease; CTRL, healthy subjects; SPK, simultaneous kidney-pancreas transplantation; K+T1D, kidney transplantation alone in type 1 diabetes; IGF-I, insulin-like growth factor 1; IGFBP3, insulin-like growth factor binding protein 3.

FIG. 15. Expression of cell lineages markers in mini-guts exposed to different culturing conditions. A1-A4, B1-B4, C1-C4, D1-D4, E1-E4. Representative images (O1× magnification) of citokeratin 20 (KRT20), vimentin, Synaptofisin and Aldehyde Dehydrogenase (ALDH) expression in mini-guts obtained from crypts isolated from healthy subjects, CTRL (A1-A4), and T1D+ESRD individuals (B1-B4), cultured with IGFBP3 (C1-C4), Glucose 35 mM (D1-D4), and Glucose 35 mM)+long-standing T1D serum (T1D+ESRD serum)+IGF-I (E1-E4). Immunofluorescence confirmed that expression of all lineages markers is reduced in mini-guts obtained from T1D+ESRD individuals as compared to CTRL (A1-A4, B1-B4), with ALDH being the least expressed marker (B4). Decreased ALDH expression was also detected in IGFBP3-treated mini-guts (C4), while mini-guts exposed to high glucose and long-standing T1D serum and treated with IGF-I showed evident ALDH expression recovery. F. Bar graph representing expression of TMEM219, KRT20, Epithelial-cell adhesion molecule (EpCam) and Chromogranin A (CHGA) on non-stem cells (EphB2⁻ cells) measured by quantitative RT-PCR. All samples were run in triplicate and normalized to the ACTB relative expression level using the ΔΔCt method. Results are expressed as mean±SEM. Abbreviations: T1D, type 1 diabetes; ESRD, end stage renal disease; CTRL, healthy subjects; IGF-I, insulin-like growth factor 1; IGFBP3, insulin-like growth factor binding protein 3; IF, immunofluorescence; KRT20, citokeratin 20, ALDH, Aldehyde Dehydrogenase, EpCam, epithelial cell adhesion molecule; CHGA, Chromogranin A; RT-PCR, real-time polymerase chain reaction; ACTB, beta actin.

FIG. 16. Selection strategy to test candidate proteins in in vitro mini-guts assay. Flow chart depicting the strategy used to select protein candidates based on proteomic profile to be tested in in vitro mini-guts assay.

FIG. 17. Analysis of developed mini-guts using the crypt domain quantitative criteria. A-P. Bar graphs grouping % of developed mini-guts with at least 1 crypt domain detectable in different conditions already reported throughout the paper.

FIG. 18. Peripheral IGFBP3 levels are increased in individuals with inflammatory bowel disease as compared to healthy subjects.

FIG. 19. IGFBP3 peripheral levels are increased in pre-diabetic and diabetic conditions in T1D (A) and T2D human subjects (B). *p<0.05, ** p<0.01, *** p<0.001. Abbreviations: IGFBP3, insulin-like growth factor binding protein 3; CTRL, healthy subjects; T1D, type 1 diabetes; T2D, type 2 diabetes; AutoAb positive: non diabetic subjects at risk for developing T1D with detected positivity of Antibodies against islets peptides; IGT: impaired glucose tolerance measured at the OGTT (oral glucose tolerance test) in fasting and non-fasting condition. NGT: normal glucose tolerance measured at the OGTT. IFG: impaired fasting glucose tolerance measured at OGTT and resulting positive only in fasting conditions.

FIG. 20. IGFBP3 peripheral levels increase in pre-diabetic and diabetic conditions in murine models of T1D (A) and T2D (B). *p<0.05, ** p<0.01, *** p<0.001. Abbreviations: C57BL6/J, B6 mice; B6, naïve mice; NOD, non-obese diabetic mice; HFD, high-fat diet, IGFBP3, insulin-like growth factor binding protein 3.

FIG. 21. IGFBP3 production in primary human hepatocytes increases during glucose exposure (11 mM, 20 mM, 35 mM) (A) and inflammation (IFNγ 1,000 U/ml, plus Il-1β 2 ng/ml) (B). *p<0.05, ** p<0.01, *** p<0.001. Abbreviations: INF, inflammation (IFNγ+Il-1β); mM, millimolar; IGFBP3, insulin-like growth factor binding protein 3.

FIG. 22. TMEM219 is expressed on human islets (A-C). *p<0.05, ** p<0.01, *** p<0.001. Abbreviations: β-ACT, beta actin.

FIG. 23. TMEM219 is expressed on murine islets (A) and on a murine beta cell line (B-D). *p<0.05, ** p<0.01, *** p<0.001. Abbreviations: β-TC, murine beta cell line; β-ACT, beta actin.

FIG. 24. IGFBP3 (50 ng/ml) increases apoptosis and caspase8 expression (A-B) and reduces insulin release and expression (C, D1-D2, E) to a greater extent as compared to pro-inflammatory stimuli (IFNγ+Il-1β) in a murine beta cell line in vitro. *p<0.05, ** p<0.01, *** p<0.001. Abbreviations: IFNγ, interferon gamma; IL-1β, interleukin beta; IGFBP3, insulin-like growth factor binding protein 3; β-TC, murine beta cell line.

FIG. 25. IGFBP3 (50 ng/ml) increases apoptosis (A) and caspase8 expression in murine islets (B with a reduction of insulin (C) in vitro. *p<0.05, ** p<0.01, *** p<0.001.

FIG. 26. IGFBP3 (50 ng/ml) increases apoptosis and caspase8 expression in human islets (A-B and C1-C2) and reduces insulin expression (D1-D2, E) in vitro. *p<0.05, ** p<0.01, *** p<0.001. Abbreviations: Pi, Propidium Iodide; M30, monoclonal antibody M30 that recognizes caspase-cleaved cytokeratin 18; INS, insulin, IGFBP3, insulin-like growth factor binding protein 3.

FIG. 27. IGFBP3 injection (150 μg/day for 15 days) in C57BL/6 mice alters islet morphology in vivo after 8 weeks of diabetes (A1-A6). Abbreviations: STZ, streptozotocin; B6, naïve C57BL6/J mice.

FIG. 28. Ecto-TMEM219 (130 ng/ml) prevents IGFBP3-associated apoptotic effects on murine beta cell line (A-B, C1-C3). *p<0.05, ** p<0.01, *** p<0.001. Abbreviations: 3-TC, murine beta cell line; INS, insulin, IGFBP3, insulin-like growth factor binding protein 3.

FIG. 29. Ecto-TMEM219 treatment (130 ng/ml) near-normalizes casapse 8 and insulin expression in murine islets in vitro. *p<0.05, ** p<0.01, *** p<0.001. Abbreviations: IGFBP3, insulin-like growth factor binding protein 3.

FIG. 30. Ecto-TMEM219 (130 ng/ml) prevents IGFBP3-associated apoptotic effects on human islets (A-B, C1-C3). *p<0.05, ** p<0.01, *** p<0.001. Abbreviations: M30, monoclonal antibody M30 that recognizes caspase-cleaved cytokeratin 18; INS, insulin; IGFBP3, insulin-like growth factor binding protein 3.

FIG. 31. Ecto-TMEM219 treatment (130 ng/ml) in diabetic mice rescues serum insulin (A, C) and blood glucose levels (B). *p<0.05, ** p<0.01, *** p<0.001.

FIG. 32. Working Hypothesis. Abbreviations: IGFBP3, insulin-like growth factor binding protein 3; IGF-I, insulin-like growth factor 1; IGF-IR, insulin-like growth factor 1 receptor.

DETAILED DESCRIPTION OF THE INVENTION Example 1 Material and Methods

60 individuals with long-standing T1D (T1D+ESRD) registered on the waiting list for simultaneous pancreas-kidney transplantation (SPK) were enrolled in the study and compared with 20 healthy subjects matched for age and gender (CTRL). Assessment of gastrointestinal symptoms, intestinal motility and intestinal mucosa pathology defined DE. CoSCs were identified on colonic purified crypts based on the expression of CoSC specific markers (flow-cytometry, RT-PCR, Western Blot, transcriptome profiling). CoSCs self-renewal properties were assessed by evaluating the % of in vitro developed mini-guts and by characterizing their expression of cell lineages markers in different conditions (FIG. 15). Broad serum proteomic was used to detect circulating factors that may regulate CoSCs and candidate factors were then tested in the in vitro mini-gut assay (FIG. 16). Detailed methods and statistical analysis are described below. The Study was approved by the Institutional Review Board of Istituto di Ricovero e Cura a Carattere Scientifico Ospedale San Raffaele, Milano, Italy (Enteropathy-Pancreas KidneyTransplantation/01 Secchi/Fiorina).

Patients and Study Design

60 individuals with T1D+ESRD registered on the waiting list for simultaneous pancreas-kidney transplantation (SPK) matched for (age 41 to 43 years old), gender, and duration of T1D (29.4±1.8 years) were enrolled in the study. 20 healthy subjects matched for age and gender (CTRL), with normal renal function and normal glycometabolic parameters, were studied as well. T1D+ESRD subjects were all on intensive insulin treatment at the time of enrollment in the study, while the CTRL group was not being administered any medication. All T1D+ESRD subjects were on the same treatment as antiplatelet therapy (ASA) and anti-hypertension (angiotensin-converting-enzyme inhibitors), while 40 out of 60 received statins when enrolled in the study. Subjects with clear signs of inflammatory bowel diseases as well as celiac disease were not enrolled.

T1D+ESRD individuals were followed up for 8 years (mean follow-up: 8.6±1.1 years) after receiving either SPK (n=30) or K+T1D (n=30) transplantation according to the macroscopic surgical evaluation at the time of transplantation. Individuals taking an oral anticoagulant agent were not included. SPK individuals were all insulin-independent for the entire follow-up period, whereas K+T1D individuals were on intensive subcutaneous insulin therapy. All subjects provided informed consent before study enrollment. Studies not included in the routine clinical follow-up were covered by an appropriate Institutional Review Board approval (Enteropatia-trapianto/01 Secchi/Fiorina).

Transplantation and Immunosuppression

Organs for transplantation were obtained from deceased donors through the “North Italia Transplant” organ procurement consortium (NITp, Milan). After induction with ATG (thymoglobulin, IMTIX, SANGSTAT), immunosuppression was maintained using cyclosporine (through levels between 100-250 ng/ml) or FK506 (through levels between 10-15 ng/ml), mycophenolate mofetil (500-2000 mg/day), and methylprednisolone (10 mg/day). Steroids were withdrawn within 3-6 months after transplantation. All patients included in the T1D+ESRD and SPK groups were on anti-platelet therapy (80% ASA and 20% ticlopidine) to prevent graft or fistula thrombosis. Metabolic status, renal function and blood pressure were examined during enrolment and after transplantation every 2 years thereafter. The estimate glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease (MDRD) formula (Levey et al., 1999).

The Gastrointestinal Symptom Rating Scale (GSRS)

Gastrointestinal symptoms were evaluated by GSRS questionnaire in healthy subjects, in long-standing T1D individuals (T1D+ESRD) and in SPK and K+T1D groups at 2, 4 and 8 years after transplantation. The Gastrointestinal Symptom Rating Scale (GSRS) is a questionnaire consisting of 15 items with a seven-graded Likert scale defined by descriptive anchors (Svedlund et al., 1988). The questionnaire was originally constructed as an interview-based rating scale designed to evaluate a wide range of gastrointestinal symptoms and was later modified to become a self-administered questionnaire. The higher the scores, the more severe the symptoms: the scale ranges from a minimum value of 1 to a maximum value of 7. If an individual's participation in the study is discontinued, the value at the last available observation will be carried forward in the analysis. The items can be grouped into five dimensions previously identified on the basis of a factor analysis: abdominal pain syndrome (three items), reflux syndrome (two items), indigestion syndrome (four items), diarrhea syndrome (three items) and constipation syndrome (three items).

Anorectal Manometry

Data on anorectal manometry were already available in healthy subjects, and were compared with those obtained by performing anorectal manometry in long-standing T1D individuals (T1D+ESRD) using a custom-designed, open-tip, 14-Fr diameter, PVC probe with seven lumens and a 4-cm latex balloon tied at the end of the probe (Bioengineering Laboratories Plc., Milan, Italy) (Carrington et al., 2014; Remes-Troche et al., 2010). The sphincter length was measured after a 10-minute run-in period, anal pressure was recorded for 15 minutes in resting conditions. Subjects were then instructed to squeeze the anus as tightly as possible and for as long as possible—for at least 20 seconds. Inventors' study evaluated the following items: Resting Tone, Contraction Tone, Reflex Response, and Urgency Response.

Pathology, Immunohistochemistry and Electron Microscopy

Colorectal endoscopy procedure was performed in healthy subjects, in long-standing T1D individuals (T1D+ESRD) at baseline and in SPK and K+T1D groups at 2, 4, and 8 years after transplantation using a Welch Allyn optic sigmoid scope. Intestinal mucosal samples were fixed in buffered formalin (formaldehyde 4% w/v and acetate buffer 0.05 M) and routinely processed in paraffin wax. 3 μm-thick sections of each enrolled case were stained with Hematoxylin & Eosin (H&E) for morphological evaluations. For immunohistochemistry, 3 μm-thick sections were mounted on poly-L-lysine coated slides, deparaffinized and hydrated through graded alcohols to water. After antigen retrieval, performed by dipping sections in 0.01 M citrate buffer, pH 6 for 10 minutes in a microwave oven at 650 W as well as endogenous peroxidase activity inhibition, performed by dipping sections in 3% hydrogen peroxide for 10 minutes, incubation with primary antibodies was performed at 4° C. for 18-20 hours, followed by the avidin-biotin complex procedure (Hsu et al., 1981). Immunoreactions were developed using 0.03% 3,3′diaminobenzidine tetrahydrochloride, and then sections were counterstained with Harris' hematoxylin. The following antibodies were used: Ki67 (monoclonal, clone MIB1, 1:100 dilution, Dako, Carpinteria, Calif., USA), aldehyde dehydrogenase (monoclonal, clone 44/ALDH, 1:1000 dilution, Transduction Laboratories, Franklin Lakes, N.J., USA), EphB2 (monoclonal, clone 48CT12.6.4, 1:200 dilution, Lifespan Biosciences, Seattle, Wash., USA), LGR5 (monoclonal, clone 2A2, 1:100 dilution, Origene Technologies, Rockville, Md., USA), hTERT (monoclonal, clone Y182, 1:500 dilution, Millipore, Billerica, Mass., USA), glicentin (polyclonal, 1:1250 dilution, Milab, Malmo, Sweden), pancreatic polypeptide (polyclonal, 1:500 dilution, Peninsula, Belmont, Calif., USA), PYY (polyclonal, 1:1000 dilution, Biogenesis, Bournemouth, UK), serotonin (monoclonal, clone YC5, 1:50 dilution, Biogenesis), somatostatin (polyclonal, 1:550 dilution, Dako), IGF-I (polyclonal, 1:500, Abcam) and IGF-1R (polyclonal, 1:100, Cell Signaling Technologies), (Fiorina et al., 2003). For ultrastructural studies, samples were fixed for 2 hours at 4° C. in a mixture of 2% paraformaldehyde and 2% glutaraldehyde in 0.05 M cacodylate buffer, pH 7.3. They were post-fixed in 1% osmium tetroxide for 1 hour at room temperature, then dehydrated and embedded in Epon-Araldite. Ultrathin sections were cut with a diamond knife and mounted on 200-mesh nickel grids, previously coated with a Formvar film. Ultrathin sections were stained with aqueous uranyl acetate and Reynold's lead citrate solutions and subsequently examined with a Philips Morgagni 268D electron microscope. Cases were grouped according to the number of neuroendocrine vesicles (n>3 and n<3) for statistical analysis. For crypt isolation, tissue was collected in a sample containing a mixture of antibiotics and processed as described in the next paragraph. The immunostaining intensity for EphB2 was graded as 1 (negative EphB2 gradient to few cells positive per crypt per field) to 5 (strong EphB2 gradient in all longitudinal crypts). An anti-IGFBP3 primary antibody (polyclonal, 1:50 dilution, Sigma Aldrich) was immunohistochemically tested in liver biopsies from patients with type 1 diabetes. Liver biopsies without pathological findings were used as controls. All of these tissue samples came from the files stored at the Unit of Pathology of the Department of Biomedical, Biotechnological, and Translational Sciences, University of Parma, Parma, Italy. The immunostaining intensity was graded as 1 (mild), 2 (moderate), and 3 (strong), while its diffusion as 1 (focal), 2 (zonal), and 3 (diffuse).

Immunoflurescence

Immunofluorescence samples obtained from liver biopsies were observed using a confocal system (LSM 510 Meta scan head integrated with the Axiovert 200 M inverted microscope; Carl Zeiss, Jena, Germany) with a 63× oil objective. Images were acquired in multitrack mode, using consecutive and independent optical pathways. The following primary antibodies were used: rabbit IGFBP3 (1:10, Sigma) mouse Hep Par-1 (1:20, monoclonal, Dako), mouse CD163 (1:10, cloneMRQ26, CellMarque).

Mini-guts co-cultured with/without IGFBP3, with/without long-standing T1D serum+high glucose (35 mM Glucose) and those obtained from crypts of T1D+ESRD individuals, were stained with Vimentin, Citocheratin 20, Aldheide Dehydrogenase and Synaptofisin for immunofluorescence analysis to assess expression of cell lineages markers (FIG. 15: A1-A4, B1-B4, C1-C4, D1-D4, E1-E4). The following primary antibodies were used: mouse vimentin (1:80, monoclonal, clone: V9 Dako) mouse Aldheyde (1:1000, monoclonal, clone: 44, BD), mouse citocherain 20 (1:100, monoclonal, clone:Ks20.8, Dako) and Synaptofisin (1:100, monoclonal, clone: syn88, BioGenex).

In Situ Hybridization

Paraffin sections of human colon mucosa were de-paraffinized and re-hydrated according to standard procedures. After treatment of sections using 0.2M HCl for 15 minutes at room temperature, sections were washed 3 times in PBS and incubated for 15 min at 37° C. in proteinase K (30 μg/ml in PBS). 0.2% glycine in PBS was added for 1 minute in order to neutralize Proteinase K activity, and samples were washed twice in PBS. After post-fixation in 4% PFA for 10 min at room temperature and 3 washes in PBS, histone acetylation was achieved by incubating samples two times for 5 min in an aqueous solution containing 1.5% triethanolamine, 0.15% HCl, and 0.6% acetic anhydride. Samples were then washed and pre-hybridized for 1 hour at 68° C. in hybridization solution (50% formamide, 5×SSC, pH4.5, 2% Blocking Reagent (Roche), 0.05% CHAPS (Sigma), 5 mM EDTA, 50 μg/ml Heparin (Sigma) and 50 μg/ml yeast RNA. For TMEM219, the digoxigenin-labelled probe was diluted 750 ng/ml in hybridization solution and incubated for 24 hrs at 65° C. Post-hybridization washes were performed 3×20 min in 50% Formamide/2×SSC at 65° C. Sections were rinsed in TBS-T buffer (0.1M TrisHCl pH7.5, 0.15M NaCl, 0.1% Tween20) and blocked for 30 min at room temperature in Blocking Solution (0.5% Blocking Reagent, 10% sheep serum in TBS-T). Sheep anti-DIG antibody (Fab fragment, Roche) was diluted 1/2000 in Blocking Solution and incubated overnight at 4° C. After this, samples were washed in TBS-T and then in NTM buffer (0.1M Tris pH9.5, 0.1M NaCl, 0.05M MgCl2) and developed in NBT/BCIP solution (Roche) for 24 hrs.

CoSC Characterization Crypt Purification

Muscle layer and sub-mucosa were carefully removed from human fresh rectal biopsy specimens, and mucosa was incubated with a mixture of antibiotics (Normocin, [Invivogen, San Diego, Calif. 92121, USA], Gentamycin [Invitrogen, Carlsbad, Calif., USA] and Fungizone [Invitrogen]) for 15 minutes at room temperature (RT). Next, tissue was cut into small pieces and incubated with 10 mM Dithiotreitol (DTT) (Sigma, St. Louis, Mo. 63103, USA) in PBS 2-3 times for 5 minutes at RT. Samples were then transferred to 8 mM EDTA in PBS and slowly rotated for 60-75 minutes at 4° C. Supernatant was replaced by fresh PBS, and vigorous shaking of the sample yielded supernatants enriched in colonic crypts. Fetal bovine serum (FBS, Sigma) was added to a final concentration of 5%, and fractions were centrifuged at 40×g for 2 minutes in order to remove single cells. This washing procedure was repeated 3 times with Advanced DMEM/F12 (ADF, Gibco) medium supplemented with 2 mM GlutaMax (Invitrogen), 10 mM HEPES (Sigma), and 5% FBS (Sigma).

200-300 isolated human colonic crypt units were mixed with 50 μl matrigel and plated on pre-warmed 24-well culture dishes as already described. After solidification (15-20 minutes at 37° C.), crypts were overlaid with 600 μl complete crypt culture medium [Wnt3a-conditioned medium and Advanced DMEM/F12 (Life Technologies, Grand Island, N.Y.) 50:50, supplemented with Glutamax, 10 mM HEPES, N-2 [1×], B-27 without retinoic acid [1×], 10 mM Nicotinamide, 1 mM N-Acetyl-L-cysteine, 50 ng/ml human EGF (Life Technologies, Grand Island, N.Y.), 1 μg/ml RSPO1 (Sino Biological, Beijing, China), 100 ng/ml human Noggin (Peprotech, Rocky Hill, N.J., USA), 1 μg/ml Gastrin (Sigma-Aldrich, St. Louis, Mo.), 500 nM LY2157299 (Axon MedChem, Groningen, The Netherlands), 10 μM SB202190 (Sigma) and 0.01 μM PGE2 (Sigma)]. Medium was replaced every other day. Rock inhibitor Y-27632 (10 VM, Sigma) was added to the cultures for the first 2-3 days. Purified crypts were directly cultured for 8 days. Cell Lineages markers for enterocytes and enteroendocrine cells were assessed in the mini-guts and in the EphB2⁺ and EphB2⁻ sorted single cells with RT-PCR by testing: CHGA, KRT20 and EPCAM (Life Technologies, Grand Island, N.Y.). Colony forming efficiency (%) was evaluated on freshly isolated crypts in order to exclude that the bioptic procedure and the isolation processing could have compromized their efficiency in forming mini-guts in in vitro culture. DAPI staining was performed to confirm number of nuclei in freshly isolated crypts from CTRL and T1D+ESRD subjects. Developed mini-guts with at least 1 crypt domain were also counted and percentage was calculated in order to add a more quantitative criteria to measure developed mini-guts (FIG. 17: A-P). Insulin and glucose levels measured on long-standing T1D (T1D+ESRD) and CTRL serum are reported below:

Glucose levels (T1D+ESRD vs. CTRL, 178±47.5 vs 90±5.5 mg/dl, p0.0001);

Insulin levels (T1D+ESRD vs. CTRL, 12.9±4.6 vs 5.8±1.6 μIU/ml, p=0.009).

Flow Cytometry

The expression of the CoSC markers EphB2 (APC anti-human EphB2 antibody, R&D, Minneapolis, Minn.) and LGR5 (PE anti-human LGR5, Origene, Rockville, Md.) was determined by flow cytometry by excluding CD45- and CD11b-positive cells (V450 anti-human CD45 and CD1 b, BD Biosciences, San Jose, Calif.). Propidium iodide (PI) was added (10 μg/ml) to exclude dead cells. EphB2⁺ cells were also sorted by flow cytometry to obtain a single cell suspension for culturing purposes. Intracellular detection of human-tert (hTERT) was performed by permeabilizing cells and staining with primary anti-human hTERT antibody (GeneTex, Irvine, Calif.) followed by DAPI anti-goat secondary antibody (Life Technologies). With regard to the analysis, cells were all first gated as PI⁻ before the assessment of other surface or intracellular markers. Samples were run on a BD LSR-Fortessa and analyzed by FSC Express 3.0 (DeNovo Software, Los Angeles, Calif., USA).

In Vitro Mini-Gut Generation Study

Crypts were isolated from healthy subject rectal biopsy samples and cultured as previously described to generate mini-guts. To create hyperglycemic conditions, the culturing medium was modified by adding glucose at different concentrations (35 mM: high glucose; 5 mM: normal glucose). To mimic uremic conditions, human uremic serum obtained from long-standing T1D individuals with ESRD was added to crypts, which were cultured as reported in the crypt culturing methods section. After 8 days, crypts were collected, and the morphology, mini-gut growth, expression of intestinal signature markers (EphB2, LGR5, h-TERT), IGF-IR and TMEM219 (Life Technologies), and Caspase 9 (Life Technologies) were examined using RT-PCR. A pan-caspase inhibitor (caspase inhibitor Z-VAD-FMK, 20 mM, Promega, Madison, Wis.), a Caspase 8 selective inhibitor (Z-IETD-FMK, BD Pharmingen), a Caspase 9 selective inhibitor (Z-LEHD-FMK, BD Pharmingen), a caspase3 inhibitor Z-DEVD-FMK (BD Pharmingen) were used in vitro in mini-guts to confirm the antiapoptotic effect of IGFBP3.

To culture isolated crypts with crypts culturing medium containing healthy subjects human serum, namely CTRL serum, in place of regular FBS, L-Wnt3 cells were grown in 10% CTRL serum to generate conditioned medium that was further added 50:50 to Advanced DMEM/F12 medium in order to obtain the crypts culture medium as previously described (see Crypt purification).

To assess the properties of sorted EphB2⁺ cells in generating mini-guts, 2000 sorted cells were mixed with 50 μl matrigel and plated on pre-warmed 24-well culture dishes. After solidification of the matrigel (10-15 min at 37° C.), cells were overlaid with “single cell growth medium” (=complete crypt culture medium+10 M Rock inhibitor Y-27623). Medium was replaced with fresh single cell growth medium every other day. Rock inhibitor was included in the culture medium for seven to nine days.

Immunoblotting

Total proteins of intestinal bioptic samples were extracted in Laemmli buffer (Tris-HCl 62.5 mmol/l, pH 6.8, 20% glycerol, 2% SDS, 5% β-mercaptoethanol) and their concentration was measured (Lowry et al., 1951). 35 μg of total protein was electrophoresed on 7% SDS-PAGE gels and blotted onto nitrocellulose (Schleicher & Schuell, Dassel, Germany). Blots were then stained with Ponceau S. Membranes were blocked for 1 h in TBS (Tris [10 mmol/1], NaCl [150 mmol/1]), 0.1% Tween-20, 5% non-fat dry milk, pH 7.4 at 25° C., incubated for 12 h with 200 mg/ml of a polyclonal anti-goat EphB2 antibody or polyclonal anti-goat LGR5 antibody (Santa Cruz Biotechnology, Santa Cruz, Calif., USA) or monoclonal IGF-IR (Santa Cruz Biotechnology) and polyclonal TMEM219 (R&D, Minneapolis, Minn.) diluted 1:200 or with a monoclonal mouse anti-3-actin antibody (Santa Cruz Biotechnology) diluted 1:1000 in TBS-5% milk at 4° C., washed four times with TBS-0.1% Tween-20, then incubated with a peroxidase-labeled rabbit anti-goat IgG secondary antibody (or rabbit anti mouse for 3-actin) diluted 1:1000 (Santa Cruz Biotechnology) in TBS-5% milk, and finally washed with TBS-0.1% Tween-20. The resulting bands were visualized using enhanced chemiluminescence (SuperSignal; Pierce, Rockford, Ill., USA).

Live Imaging of Intestinal Crypt Growth

Live imaging of mini-guts, obtained by purification and culture of intestinal crypts of CTRL, T1D+ESRD and SPK individuals, was performed on a Zeiss Axiovert S100 equipped with environmental control (from Oko-Lab, Italy) with a chamber in which a humidified premixed gas consisting of 5% CO₂ and 95% air was infused, and the whole setup was set at 37° C. Images were acquired at 20-minute intervals for 72 hours. Images were acquired and processed using Time Lapse (Oko-Lab, Italy) and, if necessary, image editing was performed using Adobe Photoshop Elements 7.0.

Morphology Imaging Analysis

The images of mini-guts were taken at day 0, 5 and 8 days by inverted microscopy Leica DH/RB and acquired with Axio Vision AC Release 4.3. Pictures reported in figures represent mini-guts at day 5, 10× magnification.

Transcriptome Profiling

Total RNA was isolated from purified intestinal crypt suspension using the RNeasy Mini Kit (Qiagen, Valencia, Calif.) with on-column DNase I digestion. Next, 3 μg total RNA from each sample was reverse-transcribed using the RT2 First Strand kit (C-03; SABiosciences, Frederick, Md.). The inventors used the Human Stem Cell RT2 Profiler PCR Arrays (PAHS-405Z), the human Stem Cell Signaling PCR Array (PAHS-047Z,) and a custom array with the following genes: AXIN2, OLFM4, BMI1, RNF43, CDCA7, SLC12A2, CDK6, SOX9, DKC1, ZNRF3, ETS2, EPHB2, FAM84A, LGR5, GPX2, ACTB (SABiosciences). The Profiler PCR Arrays measure quantitatively the expression of a panel of genes using SYBR Green-based real-time PCR (Kosinski et al., 2007). To assess the transcriptome profiling of apoptotic markers and oxidative stress markers the Human Apoptosis PCR Arrays (PAHS-012Z, SABiosciences) and the Human Oxidative Stress PCR Arrays (PAHS-065Z, SABiosciences) were used.

qRT-PCR Analysis

RNA from purified intestinal crypts was extracted using Trizol Reagent (Invitrogen), and qRT-PCR analysis was performed using TaqMan assays (Life Technologies, Grand Island, N.Y.) according to the manufacturer's instructions. The normalized expression values were determined using the ΔΔCt method. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) data were normalized for the expression of ACTB, and ΔΔCt values were calculated. Statistical analysis compared gene expression across all cell populations for each patient via one-way ANOVA followed by Bonferroni post-test for multiple comparisons between the population of interest and all other populations. Statistical analysis was performed also by using the software available RT² profiler PCR Array Data Analysis (Qiagen). For two groups comparison Student t test was employed. Analysis was performed in triplicates after isolation of fresh crypts and/or after 8 days of culture of miniguts. Table I-B reports the main characteristics of primers used.

TABLE I-B Primers Gene Refseq Band Size Reference Symbol UniGene # Accession # (bp) Position LGR5 Hs.658889 NM_003667 91 1665 EPHB2 Hs.523329 NM_004442 68 2908 TERT Hs.492203 NM_198253 106 1072 ACTB Hs.520640 NM_001101 174 730 IGF-IR Hs.643120 NM_000875.3 64 2248 TMEM219 Hs.460574 NM_001083613.1 60 726 KRT20 Hs.84905 NM_019010.2 75 974 CHGA Hs.150793 NM_001275.3 115 521 EpcaM Hs.542050 NM_002354.2 95 784 LRP1 Hs.162757 NM_002332.2 64 656 TGFbR1 Hs.494622 NM_001130916.1 73 646 TGFbR2 Hs.604277 NM_001024847.2 70 1981 Caspase 8 Hs.599762 NM_001080124.1 124 648 Caspase 9 Hs.329502 NM_001229.4 143 1405

ELISA Assay

IGF-I and IGFBP3 levels in the pooled sera/palsma of all groups of subjects and in all groups of treated and untreated mice was assessed using commercially available ELISA kits, according to the manufacturer's instructions (R&D and Sigma).

Human immortalized hepatoma cell line HuH-7 was cultured for 5 days in DMEM 10% FBS at different glucose concentrations: 5.5 mM, 20 mM and 35.5 mM. Culturing supernatant was collected, and IGFBP3 was assessed using an IGFBP3 ELISA kit (Sigma) according to the manufacturer's instructions. Collected cells were separated by trypsin and counted with a hemacytometer.

Insulin levels were assayed with a microparticle enzyme immunoassay (Mercodia Iso-Insulin ELISA) with intra- and inter-assay coefficients of variation (CVs) of 3.0% and 5.0%.

Recombinant Proteins and Interventional Studies

Recombinant human IGF-I (Sigma, 13769), (IGF-I), recombinant human IGFBP3 (Life Technologies, 10430H07H5), (IGFBP3), and anti-IGF-IR (Selleckchem, Boston, OSI-906) were added to crypt cultures at day +2 from isolation. IGFBP3 (Reprokine, Valley Cottage, N.Y.) was administered to naïve and to STZ-treated B6 mice at 0.3 mg/mouse/day for 15 days; IGF-I (Reprokine) and ecto TMEM219 were administered in vivo to STZ-treated B6 mice after 2 weeks of diabetes at a dose of 5 μg/mouse/day for 20 days and 100 μg/mouse/day for 15 days respectively.

Other molecules tested in in vitro mini-guts assay and added to crypt cultures at day +2 from isolation: Adiponectin (R&D), Thymosin J34 (Abcam), C-reactive protein (Merck Millipore), Cystatin C (Cell Signaling Technologies), Chromogranin A (Life Technologies), Fructose-bisphosphate aldolase (Novoprotein), Osteopontin (R&D), Ribonuclease pancreatic (RNASE, Novoprotein), Serum amyloid A protein (Abcam), Mannan-binding lectin serine protease 1 (MASP1, Novoprotein), Tumor necrosis factor-alpha (TNF-alpha, R&D), FaS Ligand (FasL, R&D). Hydrogen peroxide (H2O2, 50 μM) was also tested in the mini-guts assay.

Generation of Recombinant Human Ecto TMEM219

Recombinant human ecto-TMEM219 was generated using E. coli as expression host for synthesis. Briefly, gene sequence of extracellular TMEM219 was obtained: THRTGLRSPDIPQDWVSFLRSFGQLTLCPRNGTVTGKWRGSHVVGLLTTLNFGDGPDR NKTRTFQATVLGSQMGLKGSSAGQLVLITARVTTERTAGTCLYFSAVPGILPSSQPPISC SEEGAGNATLSPRMGEECVSVWSHEGLVLTKLLTSEELALCGSR (SEQ ID No. 2).

The DNA sequence of extracellular TMEM219 was cloned into a high copy-number plasmid containing the lac promoter, which is then transformed into the bacterium E. coli. Addition of IPTG (a lactose analog) activated the lac promoter and caused the bacteria to express extracellular TMEM219 (ecto TMEM219). SDS-PAGE and Western Blot were used to confirm purity higher than 90%. The molecular weight of the new generated protein recombinant human ecto TMEM219 was 80 kda.

Crypts from healthy subjects were isolated and cultured as previously described and ecto-TMEM219 was added to the culture at three concentrations (260 ng/ml, 130 ng/ml and 75 ng/ml) as compared to IGFBP3 concentration used (2:1, 1:1 and 1:2) and appropriate controls were set up for each concentration. After 8 days of culture, caspase 8 and 9 expression, CoSCSC signature markers (EphB2 and LGR5) expression, number of developed mini-guts, were further assessed.

Small RNA Interference

Isolated crypts obtained from healthy subjects were grown to generate in vitro mini-guts in complete medium and in culturing medium modified by adding high glucose and long-standing T1D serum as previously described (see in vitro mini-gut generation study in online methods). After 72 h of culture, which allowed the crypts to recover, 750 ng of small interfering RNA (siRNA; Flexitube siRNA SI04381013, Qiagen, Valencia, Calif.) in 100 μl culture medium without serum and with 6 μl HiPerFect Transfection Reagent (Qiagen) were incubated at room temperature to allow for the formation of transfection complexes. Crypts were incubated with these transfection complexes under their normal growth conditions for 6 h. Analysis of gene silencing was performed at 24, 48 and 72 h by evaluating the percentage of normal mini-gut development. Control siRNA was used as a negative control to confirm the effect of gene silencing.

Proteomic Analysis

8 μl of pooled serum from 10 patients per group were depleted using a ProteoPrep 20 spin column (Sigma), thus allowing for the removal of the 20 highly abundant proteins. The procedure was twice repeated in order to obtain ˜99% depletion, according to the manufacturer's instructions. The recovered supernatant was analyzed to determine total protein concentration using the Direct Detect IR spectrophotometer and BSA as a standard. In order to obtain enough protein for proteomic analysis, 32 μl from each pool were processed as above described. 40 μg of total protein from each sample was in-solution digested using the Filter Aided Sample Preparation (FASP) protocol as reported in the literature (Wisniewski et al., 2009). Samples were desalted using C18 homemade tip columns (C18 Empore membrane, 3M) and injected into a capillary chromatographic system (EasyLC, Proxeon Biosystems, Thermo Scientific). Peptide separations were performed on a homemade 25 cm reverse phase spraying fused silica capillary column, packed with 3 μm ReproSil Pur 120 C18-AQ. A gradient of eluents A (pure water with 2% v/v ACN, 0.5% v/v acetic acid) and B (ACN with 20% v/v pure water with 0.5% v/v acetic acid) was used to achieve separation (0.15 μL/minute flow rate) (from 10 to 35% B in 230 minutes, from 35 to 50% B in 5 minutes and from 50 to 70% B in 30 minutes). Mass spectrometry analysis was performed using an LTQ-Orbitrap mass spectrometer (Thermo Scientific, Waltham, Mass.) equipped with a nanoelectrospray ion source (Proxeon Biosystems). Full scan mass spectra were acquired with the lock-mass option and resolution set to 60,000. The acquisition mass range for each sample was from m/z 300 to 1750 Da. The ten most intense doubly and triply charged ions were selected and fragmented in the ion trap using a normalized collision energy 37%. Target ions already selected for the MS/MS were dynamically excluded for 120 seconds. All MS/MS samples were analyzed using Mascot (v.2.2.07, Matrix Science, London, UK) search engine to search the UniProt_Human Complete Proteome_cp_hum_2013_12. Searches were performed with trypsin specificity, two missed cleavages allowed, cysteine carbamidomethylation as fixed modification, acetylation at protein N-terminus, and oxidation of methionine as variable modification. Mass tolerance was set to 5 ppm and 0.6 Da for precursor and fragment ions, respectively. To quantify proteins, the raw data were loaded into the MaxQuant software version 1.3.0.5 (Cox et al., 2011). Label-free protein quantification was based on the intensities of precursors. Peptides and proteins were accepted with an FDR less than 1%, two minimum peptides per protein. The experiments were performed in technical triplicates. The complete dataset of proteins, obtained by proteomic analysis (Table I-C), was analyzed by Student's t-test using MeV software v. 4_8_1. 47 proteins, which were significantly different (p-value<0.01) in control pool versus T1D-ESDR pool, were further submitted to hierarchical clustering analysis.

TABLE I-C List of quantified proteins identified by proteomic analysis. The table reports correspondence between numbers and names of proteins detected by proteomic analysis and is shown as a heat-map in FIG. 10. Original row Protein names 1 14-3-3 protein zeta/delta 4 Actin, cytoplasmic 1; Actin, cytoplasmic 1, N-terminally processed; Actin, cytoplasmic 2; Actin, cytoplasmic 2, N- terminally processed 5 Adiponectin 6 Afamin 8 Alpha-1-antichymotrypsin; Alpha-1-antichymotrypsin His-Pro- less 9 Alpha-1-antitrypsin; Short peptide from AAT 12 Alpha-2-HS-glycoprotein; Alpha-2-HS-glycoprotein chain A; Alpha-2-HS-glycoprotein chain B 13 Alpha-2-macroglobulin 14 Alpha-actinin-1 16 Angiotensinogen; Angiotensin-1; Angiotensin-2; Angiotensin-3 17 Antithrombin-III 18 Apolipoprotein A-I; Truncated apolipoprotein A-I 20 Apolipoprotein A-IV 21 Apolipoprotein B-100; Apolipoprotein B-48 22 Apolipoprotein C-I; Truncated apolipoprotein C-I 23 Apolipoprotein C-II 24 Apolipoprotein C-III 25 Apolipoprotein C-IV 26 Apolipoprotein D 28 Apolipoprotein F 29 Apolipoprotein L1 31 Apolipoprotein(a) 34 Attractin 35 Basement membrane-specific heparan sulfate proteoglycan core protein; Endorepellin; LG3 peptide 36 Beta-2-glycoprotein 1 37 Beta-2-microglobulin; Beta-2-microglobulin form pI 5.3 39 Beta-Ala-His dipeptidase 42 C4b-binding protein beta chain 43 Cadherin-1; E-Cad/CTF1; E-Cad/CTF2; E-Cad/CTF3 44 Cadherin-13 45 Cadherin-5 46 Calreticulin 50 Carboxypeptidase N subunit 2 51 Cartilage oligomeric matrix protein 54 CD44 antigen 57 Ceruloplasmin 59 Chromogranin-A; Vasostatin-1; Vasostatin-2; EA-92; ES-43; Pancreastatin; SS-18; WA-8; WE-14; LF-19; AL-11; GV-19; GR-44; ER-37 60 Clusterin; Clusterin beta chain; Clusterin alpha chain; Clusterin 62 Coagulation factor V; Coagulation factor V heavy chain; Coagulation factor V light chain 63 Coagulation factor X; Factor X light chain; Factor X heavy chain; Activated factor Xa heavy chain 65 Cofilin-1 66 Collagen alpha-3(VI) chain 68 Complement C1r subcomponent; Complement C1r subcomponent heavy chain; Complement C1r subcomponent light chain 71 Complement C2; Complement C2b fragment; Complement C2a fragment″ 72 Complement C3; Complement C3 beta chain; Complement C3 alpha chain; C3a anaphylatoxin; Complement C3b alpha chain; Complement C3c alpha chain fragment 1; Complement C3dg fragment; Complement C3g fragment; Complement C3d fragment; Complement C3f fragment; Complement C3c alpha chain fragment 2 73 Complement C4-A; Complement C4 beta chain; Complement C4-A alpha chain; C4a anaphylatoxin; C4b-A; C4d-A; Complement C4 gamma chain 74 Complement C4-B; Complement C4 beta chain; Complement C4-B alpha chain; C4a anaphylatoxin; C4b-B; C4d-B; Complement C4 gamma chain 75 Complement C5; Complement C5 beta chain; Complement C5 alpha chain; C5a anaphylatoxin; Complement C5 alpha chain 76 Complement component C1q receptor 77 Complement component C6 78 Complement component C7 84 Complement factor D 88 Complement factor I; Complement factor I heavy chain; Complement factor I light chain 89 Corticosteroid-binding globulin 90 C-reactive protein; C-reactive protein(1-205) 91 Cystatin-C 92 Cystatin-M 95 EGF-containing fibulin-like extracellular matrix protein 1 96 Endothelial protein C receptor 97 Extracellular matrix protein 1 98 Extracellular superoxide dismutase [Cu—Zn] 99 Fetuin-B 100 Fibrinogen alpha chain; Fibrinopeptide A; Fibrinogen alpha chain 101 Fibrinogen beta chain; Fibrinopeptide B; Fibrinogen beta chain 102 Fibrinogen gamma chain 103 Fibronectin; Anastellin; Ug1-Y1; Ug1-Y2; Ug1-Y3 104 Fibulin-1 105 Ficolin-3 106 Fructose-bisphosphate aldolase A; Fructose-bisphosphate aldolase 107 Galectin-3-binding protein 108 Gamma-glutamyl hydrolase 109 Gelsolin 111 Glyceraldehyde-3-phosphate dehydrogenase 112 Haptoglobin; Haptoglobin alpha chain; Haptoglobin beta chain 117 Heparin cofactor 2 122 Hypoxia up-regulated protein 1 123 Ig alpha-1 chain C region 125 Ig gamma-1 chain C region 126 Ig gamma-2 chain C region 127 Ig gamma-3 chain C region 129 Ig heavy chain V-II region SESS; Ig heavy chain V-II region OU 130 Ig heavy chain V-III region BRO; Ig heavy chain V-III region TEI; Ig heavy chain V-III region BUT; Ig heavy chain V-III region WEA 134 Ig heavy chain V-III region VH26 135 Ig kappa chain C region 136 Ig kappa chain V-I region EU; Ig kappa chain V-I region CAR 142 Ig kappa chain V-III region WOL; Ig kappa chain V-III region SIE; Ig kappa chain V-III region Ti; Ig kappa chain V-III region GOL 144 Ig kappa chain V-IV region Len 145 Ig lambda chain V-I region HA; Ig lambda chain V-I region WAH; Ig lambda chain V-II region MGC; Ig lambda chain V-II region WIN 146 Ig lambda chain V-III region LOI 148 Ig lambda-2 chain C regions; Ig lambda-3 chain C regions; Ig lambda-6 chain C region 153 Immunoglobulin lambda-like polypeptide 5; Ig lambda-1 chain C regions 154 Insulin-like growth factor-binding protein 2 155 Insulin-like growth factor-binding protein 3 156 Insulin-like growth factor-binding protein 6 158 Inter-alpha-trypsin inhibitor heavy chain H1 159 Inter-alpha-trypsin inhibitor heavy chain H2 160 Inter-alpha-trypsin inhibitor heavy chain H3 161 Inter-alpha-trypsin inhibitor heavy chain H4; 70 kDa inter-alpha- trypsin inhibitor heavy chain H4; 35 kDa inter-alpha-trypsin inhibitor heavy chain H4 164 Keratin, type I cytoskeletal 10 165 Keratin, type I cytoskeletal 9 166 Keratin, type II cytoskeletal 1 167 Kininogen-1; Kininogen-1 heavy chain; T-kinin; Bradykinin; Lysyl-bradykinin; Kininogen-1 light chain; Low molecular weight growth-promoting factor 168 Leucine-rich alpha-2-glycoprotein 171 L-lactate dehydrogenase B chain; L-lactate dehydrogenase 174 Lumican 175 Lymphatic vessel endothelial hyaluronic acid receptor 1 176 Lysozyme C 178 Mannan-binding lectin serine protease 1; Mannan-binding lectin serine protease 1 heavy chain; Mannan-binding lectin serine protease 1 light chain 180 Monocyte differentiation antigen CD14; Monocyte differentiation antigen CD14, urinary form; Monocyte differentiation antigen CD14, membrane-bound form 181 Multimerin-1; Platelet glycoprotein Ia*; 155 kDa platelet multimerin 183 Neudesin 185 Neural cell adhesion molecule L1-like protein; Processed neural cell adhesion molecule L1-like protein 187 Osteopontin 188 Peptidase inhibitor 16 189 Peptidyl-prolyl cis-trans isomerase A; Peptidyl-prolyl cis-trans isomerase 192 Phosphatidylethanolamine-binding protein 4 194 Pigment epithelium-derived factor 197 Plasminogen; Plasmin heavy chain A; Activation peptide; Angiostatin; Plasmin heavy chain A, short form; Plasmin light chain B 198 Platelet basic protein; Connective tissue-activating peptide III; TC-2; Connective tissue-activating peptide III(1-81); Beta- thromboglobulin; Neutrophil-activating peptide 2(74); Neutrophil-activating peptide 2(73); Neutrophil-activating peptide 2; TC-1; Neutrophil-activating peptide 2(1-66); Neutrophil-activating peptide 2(1-63) 199 Platelet glycoprotein Ib alpha chain; Glycocalicin 200 Plexin domain-containing protein 2 203 Profilin-1 204 Proline-rich acidic protein 1 205 Properdin 206 Prostaglandin-H2 D-isomerase 207 Protein AMBP; Alpha-1-microglobulin; Inter-alpha-trypsin inhibitor light chain; Trypstatin 209 Prothrombin; Activation peptide fragment 1; Activation peptide fragment 2; Thrombin light chain; Thrombin heavy chain 212 Receptor-type tyrosine-protein phosphatase gamma 213 Retinol-binding protein 4; Plasma retinol-binding protein(1-182); Plasma retinol-binding protein(1-181); Plasma retinol-binding protein(1-179); Plasma retinol-binding protein(1-176) 214 Rho GDP-dissociation inhibitor 2 215 Ribonuclease pancreatic 216 Scavenger receptor cysteine-rich type 1 protein M130; Soluble CD163″ 217 Secreted and transmembrane protein 1 221 Serotransferrin 222 Serum albumin 223 Serum amyloid A protein 225 Serum amyloid P-component; Serum amyloid P-component(1- 203) 226 Serum paraoxonase/arylesterase 1 228 SPARC-like protein 1 230 Talin-1 232 Tenascin-X 233 Tetranectin 234 Thrombospondin-1 235 Thrombospondin-4 236 Thymosin beta-4; Hematopoietic system regulatory peptide 237 Thyroxine-binding globulin 239 Transgelin-2 240 Trans-Golgi network integral membrane protein 2 242 Tropomyosin alpha-4 chain 243 Vascular cell adhesion protein 1 244 Vasorin 245 Vinculin 247 Vitamin K-dependent protein C; Vitamin K-dependent protein C light chain; Vitamin K-dependent protein C heavy chain; Activation peptide 248 Vitamin K-dependent protein S 249 Vitamin K-dependent protein Z 250 Vitronectin; Vitronectin V65 subunit; Vitronectin V10 subunit; Somatomedin-B 251 von Willebrand factor; von Willebrand antigen 2 254 Zinc-alpha-2-glycoprotein 258 Vitamin D-binding protein 259 Complement factor H 266 Fibulin-1 267 Mannan-binding lectin serine protease 1 270 Complement factor H-related protein 4

Strategy to Select Candidate Proteins

Among the 46 factors that segregated separately in long-standing T1D subjects and healthy controls, the inventors first selected those with a more significant difference in LFQ intensity in comparing the two groups (p>0.005), leading to the exclusion of 12 factors (FIG. 16). Next, the inventors evaluated whether altered factors may be associated with intestinal disorders and/or with the development of diabetes by searching for already reported studies and publications in the field. This led us to exclude other 12 factors. The inventors also excluded those factors mainly related to the lymphoid compartment (n=5). The inventors ended up with 17 factors. The inventors excluded cell-membrane proteins (n=4) and proceeded with testing the remaining (n=13) in the mini-gut assay. Two factors were not available to be tested in vitro. The inventors tested n=1 proteins in total.

Animal Studies

C57BL/6 (B6) mice were obtained from the Jackson Laboratory, Bar Harbor, Me. All mice were cared for and used in accordance with institutional guidelines approved by the Harvard Medical School Institutional Animal Care and Use Committee. Mice were rendered diabetic with streptozotocin injection (225 mg/kg, administered i.p.; Sigma). Diabetes was defined as blood glucose levels >250 mg/dL for 3 consecutive measures. Diabetic enteropathy was assessed as follows: briefly, the entire intestine was extracted from sacrificed mice and flushed with PBS. The extreme part of the colon was then cut and divided in two pieces. One piece of colon tissue was directly submerged in formalin while the other was cut longitudinally to expose the lumen and the internal mucosa and then submerged in formalin. Tissue was then paraffin embedded and processed for H&E and immunostaining. In addition, colonic tissue was also cut and isolation of colonic stem cells was performed as previously described (Merlos-Suarez et al., 2011). Briefly, colon was cut into 2-4 mm pieces and the fragments were washed in 30 mL ice-cold PBS. Fragments were the transferred in 50 ml tubes containing pre-warmed 20 mM EDTA-PBS and incubated at 37° C. for 30 min. After incubation the suspended tissue was transferred into tube containing 30 ml cold PBS and centrifuged. Crypts were resuspended in 13 ml cold DMEMF12, washed with PBS and digested in 5-10 ml of trypsin/DNAse solution at 37° C. for 30 min. Crypts were then resuspended in DMEMF12/EDTA, filtered in 40 micron strainer twice and washed. Finally, crypts were then resuspended in flow medium (DMEM+FBS+EDTA) and stained for anti EphB2-APC (R&D), mouse anti-CD45-PeRCP and mouse anti-CD11b-PE (BD Pharmingen). Samples were run using a FACSCalibur Analyzer and data analyzed with FlowJo. Part of the tissue was also snap frozen and stored in Tryzol to perform RT-PCR studies for the following markers:

Gene Refseq Band Size Reference Symbol: UniGene #: Accession #: (bp): Position: LGR5 Mm.42103 NM_010195.2 64 571 EPHB2 Mm.250981 NM_010142.2 85 1696 Casp8 Mm.336851 NM_001080126.1 96 1525 Casp9 Mm.88829 NM_001277932.1 68 377 GAPDH Mm. 304088 NM_008084.2 107 75

Finally, plasma and serum were collected to perform analysis of IGF-I (IGF-I ELISA kit, R&D), IGFBP3 (IGFBP3 ELISA kit, R&D) and insulin levels (Mercodia Mouse Insulin ELISA kit). Blood glucose was monitored twice a week for the 8 weeks in order to confirm diabetes onset and permanence.

Statistical Analysis

Data are presented as mean and standard error of the mean (SEM) and were tested for normal distribution with the Kolmogorov-Smirnov test and for homogeneity of variances with Levene's test. The statistical significance of differences was tested with two-tailed t-test and the chi-square (χ²) tests. Significance between the two groups was determined by two-tailed unpaired Student's t test. For multiple comparisons, the ANOVA test with Bonferroni correction was employed. All data were entered into Statistical Package for the Social Science (SPSS®, IBM®, SPSS Inc., Chicago, Ill.) and analyzed. Graphs were generated using GraphPad Prism version 5.0 (GraphPad Software, La Jolla, Calif.). All statistical tests were performed at the 5% significance level.

Results Intestinal Dysfunction and Clinical Symptoms are Present in Long-Standing T1D

The inventors first characterized intestinal morphology and function in a population of individuals with long-standing T1D and end stage renal disease (T1D+ESRD) and in healthy subjects (CTRL). Severe intestinal symptoms, such as diarrhea, abdominal pain and constipation, were evident in T1D+ESRD individuals as assessed using the Gastrointestinal Symptom Rating Scale (GSRS) questionnaire (FIG. 1: A-C). Symptoms were associated with abnormalities in anorectal sphincter function (FIG. 1: D-F). The intestinal mucosa was altered in individuals with T1D+ESRD as compared to healthy subjects, with lower number of crypts, distortion and zonal sclerosis of the lamina propria (FIG. 1: G1-G2, H). A significant reduction in epithelial cell proliferation as assessed by Ki67 (MIB1 antibody) staining (FIG. 1: I1-I2, J), signs of neural degeneration (FIG. 1: K1-K2, L) and reduction in serotonin expression in intestinal neuroendocrine cells (FIG. 1: M1-M2, N) were observed, confirming the presence of DE in these individuals.

CoSCs are Altered in Long-Standing T1D

The characterization of colonic crypts, revealed a significant reduction in EphB2⁺ expression and in the number of aldehyde dehydrogenase (Aldh)⁺ immunoreactive cells, both markers of local stem cells (Carpentino et al., 2009; Jung et al., 2011), in T1D+ESRD individuals as compared to healthy subjects (FIG. 1: O1-O2, P, Q1-Q2, R). A profound decrease was evident, upon gating on PI⁻ cells at FACS analysis (FIG. 8: A-C), in the percentage of EphB2^(hi), EphB2^(hi+)LGR5⁺ and EphB2⁺h-TERT⁺ cells isolated from intestinal crypts obtained from T1D+ESRD individuals as compared to healthy subjects (FIG. 2: A-B, C-E, FIG. 8: D-E) and was confirmed by RT-PCR (FIG. 2: F-H) and western blot (WB) analysis (FIG. 8F). Transcriptome profiling of crypts obtained from T1D+ESRD documented a decreased expression of Notch pathway (Notch1 and 2, JAG1, Dll1, Sox1 and 2), Wnt pathway (APC, FZD1, DKC1, ETS2, FAM84A, GPX2, RNF43) and BMP pathway (BMP1, BMP2, BMP3) genes, previously known pathways that control CoSCs, as compared to the expression of these genes in healthy subjects (FIG. 8G and Table II).

TABLE II List of up and down regulated stem cell target genes identified by transcriptomic profiling in CTRL vs. T1D + ESRD freshly isolated colonic crypts (at least p < 0.05). Down-regulated genes Up-regulated genes ACTC1 APC CD44 DVL1 BTRC SOX1 SOX2 WNT1 CCND2 FZD1 ADAR ACAN ALPI CD8A COL1A1 COL2A1 COL9A1 BMP1 BMP2 BMP3 CCNA2 CCNE1 CDC42 CDK1 CTNNA1 CXCL12 PARD6A CD3D CD8B MME CD4 DLL1 HDAC2 NOTCH1 DLL3 JAG1 NOTCH2 DTX2 KAT2A NUMB EP300 FGF2 FGF3 FGFR1 GDF3 ISL1 KRT15 MSX1 MYOD1 T GJA1 GJB1 GJB2 KAT8 RB1 h-TERT NCAM1 SIGMAR1 TUBB3 ABCG2 ALDH1A1 PDX1 IGF-I DHH BGLAP

Analysis of—CoSC signature genes revealed that LGR5, EphB2 (Gracz et al., 2013; Merlos-Suarez et al., 2011), h-TERT (Breault et al., 2008) and other intestinal stem cell marker genes (Hughes et al., 2011; Munoz et al., 2012; Ziskin et al., 2013) were significantly underexpressed in T1D+ESRD as compared to healthy subjects as well (FIG. 2I), confirming that the CoSCs are altered in individuals with DE.

In Vitro Generation of Mini-Guts is Altered in Long-Standing T1D

In order to evaluate CoSC self-renewal properties, the inventors used the in vitro mini-gut assay. Indeed, crypts isolated from T1D+ESRD individuals and cultured in vitro for 8 days formed small spheroid mini-guts that failed to grow as compared to healthy subjects (FIG. 2: J1, J2, K), despite a comparable viability (FIG. 8: H-I) and efficiency of forming mini-guts in both groups (FIG. 8J). To begin to elucidate the effect of circulating factors and high glucose on CoSCs, the inventors cultured isolated intestinal crypts obtained from healthy subjects in high glucose with/without serum obtained from long-standing T1D individuals in vitro for 8 days (FIG. 2: L1-L4, M). High glucose partially prevented the generation of fully mature mini-guts and synergized with serum of long-standing T1D individuals in altering CoSC self-renewal properties, such that mini-guts appeared collapsed (FIG. 2: L2-L4). Analysis of gene expression also revealed changes in the CoSC signature (FIG. 2N), thus suggesting that hyperglycemia and circulating factors act together to alter CoSC regenerative properties in long-standing T1D.

Serum Unbiased Proteomic Profiling Revealed Increased Levels of IGFBP3 in Long-Standing T1D

In order to identify potential circulating factors that may serve as enterotrophic hormones and may have a role in regulating the CoSCs, the inventors compared the serum proteome of healthy subjects with T1D+ESRD individuals using an unbiased proteomic array. A clear proteomic profile was evident in T1D+ESRD individuals as compared to healthy subjects, with more than 50% of the detected proteins segregating in either one group or the other (FIG. 3A). Some proteins were associated with diabetes, and some were growth factors or stem cell-related proteins or were potentially involved in intestinal functions (FIG. 3A). In particular, the levels of IGF-I binding proteins (IGFBP2 and 3) were detectable in long-standing T1D individuals as compared to healthy subjects, with IGFBP3 almost 5-fold increased (FIG. 3B), while IGFBP1, 4, 5 and 6 remained almost undetectable. Interestingly, in the liver of individuals with long-standing T1D, hepatocytes, but not Kuppfer cells, showed a higher IGFBP3 immunohistochemical expression as compared to healthy subjects (FIG. 3: C1-C2, FIG. 8: K, L1-L6), suggesting an increase in IGFBP3 hepatic synthesis and release. The effect of high glucose on IGFBP3 hepatic release was confirmed by the detection of increased IGFBP3 levels in the supernatant of human immortalized hepatocytes exposed to high glucose (FIG. 3D). Finally, serum levels of free IGF-I appeared significantly reduced in long-standing T1D as compared to healthy subjects (FIG. 3E), indicating that circulating IGF-I and IGFBP3 levels are altered in long-standing T1D.

Peripheral IGFBP3 and IGF-I Control CoSCs

To further elucidate the role of circulating IGF-I and IGFBP3 in the regulation of the CoSCs and of intestinal epithelial proliferation, the inventors demonstrated the expression of IGF-IR and of IGFBP3 receptor (TMEM219) on isolated crypts (FIG. 3: F, H, FIG. 8: M, N1-N2) using RT-PCR and WB (FIG. 3: F, H, FIG. 8M), and confirmed the expression of IGF-IR on CoSCs with immunostaining (FIG. 8: N1-N2), and of TMEM219 with in situ hybridization (FIG. 3: G1-G2). In order to mechanistically confirm the role of IGF-I and IGFBP3 on CoSC, the inventors tested the effect of several molecules, identified by proteomic profiling, in their in vitro mini-gut assay. Inventors' strategy to select potential targets is reported in Supplemental Information. The severely altered mini-guts generated from intestinal samples obtained from T1D+ESRD individuals were rescued by the addition of recombinant human IGF-I (IGF-I) to the culture medium (FIG. 31), while the addition of recombinant human IGFBP3 (IGFBP3) resulted in the abrogation of the positive effect observed with IGF-I, with a decreased development of mini-guts and increased formation of collapsed and distorted organoids (FIG. 31). Because IGFBP3 has been recently shown to act independently of IGF-I (Williams et al., 2007) via the IGFBP3 receptor (TMEM219)(Baxter, 2013), it was necessary to clarify whether IGFBP3 exerts its effects on CoSCs by binding IGF-I or by directly targeting TMEM219 on CoSCs. The inventors first confirmed that IGFBP3 has a direct pro apoptotic effect on CoSCs by demonstrating increased Caspase 8 and 9 expression in mini-guts obtained from healthy subjects and long-standing T1D individuals and cultured with IGFBP3 (FIG. 3J, FIG. 9: A-B), while the addition of a Pan-Caspase inhibitor (Z-VAD-FMK) or the addition of both selective inhibitors of caspases 8 and 9, but not that of other caspase cascade inhibitors (Caspase 3 inhibitor) abrogated the IGFBP3 effect (FIG. 3K). The inventors then demonstrated that the addition of IGF-I did not rescue the development of mini-guts obtained from healthy subjects and exposed to IGFBP3 (FIG. 3L), confirming that IGFBP3 may act through both a direct and indirect IGF-I mechanism. Interestingly, high glucose alone was unable to completely disrupt mini-gut growth, and anti-IGF-IR did not worsen growth and morphology of mini-guts formed from healthy subjects (FIG. 3L). The addition of IGF-I to mini-guts generated from healthy subjects, but cultured with high glucose and serum from long-standing T1D individuals, rescued mini-gut morphology, while IGFBP3 abolished the positive effect of IGF-I when added to the mini-gut culture (FIG. 3L). Interestingly, the use of healthy subjects “CTRL” serum in culturing crypts obtained from long-standing T1D nearly restored mini-guts development/morphology, indicating that circulating factors, and in particular IGF-I/IGFBP3 dyad, control CoSCs (FIG. 9: C-D). The inventors then genetically modulated TMEM219 expression by using siRNA in vitro in mini-guts obtained from healthy subjects. Knockdown of TMEM219 in mini-guts preserved their ability to grow and self-renew, despite the addition of IGFBP3 and high glucose with long-standing T1D serum (FIG. 3M). Concomitant blockade of TMEM219 by SiRNA and IGF-IR by blocking antibody did not result in any additional beneficial effect on mini-guts development despite using serum from healthy subjects or from long-standing T1D (FIG. 9E).

Other circulating proteins, which appeared altered in serum proteome of long-standing T1D individuals, were tested in the in vitro mini-gut assay and did not show any significant effect on mini-guts growth (FIG. 9: F-G). C-peptide and insulin, whose levels are commonly altered in T1D and which may interfere with IGF-I/IGFBP3 dyad by binding IGF-IR (FIG. 9H), were tested as well and did not show any effect.

To further confirm that IGF-I/IGFBP3 dyad targets effectively CoSCs and not only crypts, the inventors tested its effect on single cell-derived mini-guts. The inventors flow sorted EphB2⁺ cells from isolated crypts and established that TMEM219 was highly expressed on their surface (FIG. 4A). The inventors then cultured EphB2⁺ cells in the in vitro single cell-derived mini-gut assay and confirmed that high glucose and long-standing T1D serum exposure as well as addition of IGFBP3 significantly abrogate single cell-derived mini-guts growth, thus recapitulating the main features reported in their previous observations on crypt-derived mini-guts (FIG. 4B, FIG. 10: A1-A3). Moreover, expression of Caspase 8 and 9 was up regulated in IGFBP3-treated mini-guts and in those exposed to high glucose and long-standing T1D serum, while Ki67, marker of proliferation, was significantly under expressed (FIG. 10: B-D).

Effect of the IGF-I/IGFBP3 Dyad on Previously Known Pathways that Control CoSCs

In order to clarify the effects of IGF-I/IGFBP3 dyad on pathways previously known to be involved in CoSC niche function (i.e. Wnt/Notch/BMP), the inventors obtained from their stem cell transcriptome profile the expression of niche specific gene transcripts. IGF-I restores significantly the expression of some factors associated with Wnt/Notch signaling pathways on mini-guts obtained from crypts of T1D+ESRD (FIG. 10E, Table III), while IGFBP3 poorly affects Wnt/Notch/BMP gene expression in mini-guts obtained from crypts of healthy subjects or from those of T1D+ESRD (FIG. 10F, Table III).

TABLE III List of up and down-regulated stem cell target genes identified by transcriptomic profiling in colonic crypts obtained from CTRL and from T1D + ESRD and cultured with/without IGFBP3 and IGF-I (at least p < 0.05). Down-regulated genes Up-regulated genes CTRL + IGF-I CD44, CDH1, COL9A1 ACAN, COL2A1, DLL1, FGF2, vs. FGF3, GDF3, GJA1, IGF-I, ISL1, CTRL MME, MSX1, NCAM1, NOTCH2, PDX1, SOX1, SOX2, h-TERT CTRL + IGFBP3 CD8B, COL9A1, RB1, SOX1, h-TERT ASCL2, COL2A1, DHH, DLL1, vs. DTX1, DVL1, FGF3, FGF4, CTRL FOXA2, FRAT1, GDF2, HSPA9, IGF1, KAT2A, MSX1, MYC, NEUROG2, S100B, WNT1 T1D + ESRD + IGF-I ACTC1, CD3D, CD4, COL9A1, DTX1, ABCG2, ADAR, BMP1, BMP2, vs. FGFR1 BTRC, CDC42, CTNNA1, T1D + ESRD CXCL12, DLL1, DTX2, GDF3, HDAC2, ISL1, JAG1, NOTCH1, NOTCH2, NUMB, PARD6A, PDX1, RB1, SIGMAR1, h-TERT T1D + ESRD + IGFBP3 ABCG2, ALDH1A1, ALPI, CD3D, CD4, ASCL2, KAT2A, MYC, NCAM1, vs. CD44, CD8A, CDC42, FGF2, FGFR1, NEUROG2, SOX2 T1D + ESRD JAG1, SIGMAR1, SOX1, TUBB Abbreviations: IGF-I, insulin-like growth factor 1; IGFBP3, insulin-like grwth factor binding protein 3, CTRL, healthy subjects, T1D, type 1 diabetes, ESRD, end-stage renal disease.

This confirms that IGF-I preserves the expression of some genes involved in Wnt/Notch/BMP signaling, but also that IGFBP3 acts independently on CoSCs, without major alterations in the expression of key-target genes of the other previously known pathways.

Effect of IGF/IGFBP3 Dyad on Apoptotic Pathways in CoSCs

An extensive transcriptome analysis performed to clarify the IGFBP3 caspase-mediated effect on mini-guts, (FIG. 4: C-D, FIG. 10: G-H, Table IV), showed that addition of IGFBP3 to mini-guts grown from healthy subjects crypts, was associated with a significant up regulation of caspase-cascade activators (Caspases 8 and 9) and proapoptotic genes, while the anti-apoptotic gene Bcl2 was down regulated (FIG. 4C).

TABLE IV List of up and down-regulated pro/anti-apoptotic target genes identified by transcriptomic profiling in CTRL vs. T1D + ESRD freshly isolated colonic crypts and in those cultured with IGFBP3 and IGF-I (at least p < 0.05). Down-regulated genes Up-regulated genes T1D + ESRD BCL2, NOL3, FAS CASP1, CASP10, CASP14, CASP5, vs. CASP6, CASP7, CASP8, CASP9, CTRL CD27, CRADD, FADD, FASLG, HRK, TNFRSF10A, TNFRSF10B, TNFRSF11B, TNFRSF1A, TNFRSF1B, TNFRSF25, TNFRSF9, TNFSF8, TRADD, TRAF3 CTRL + IGF-I BNIPL3 CASP14, CASP5, CD27, CRADD, vs. FASLG, TNFRSF25, TNFSF8, CTRL TRADD CTRL + IGFBP3 BAX, BCL2 CASP5, CASP8, CASP9, FAS, vs. TNFRSF1B, TNFSF8, TRADD, CTRL TRAF3 T1D + ESRD + IGF-I CASP1, CASP10, CASP5, BCL2 vs. CASP6, CASP7, CASP8, T1D + ESRD CASP9, CRADD, FADD, TNFRSF11B, TNFRSF9, TNFSF8, TRADD, TRAF3 T1D + ESRD + IGFBP3 BAX, BCL2, NOL3, CASP9, CD27 vs. TNFRSF1B T1D + ESRD Abbreviations: IGF-I, insulin-like growth factor 1; IGFBP3, insulin-like grwth factor binding protein 3, CTRL, healthy subjects, T1D, type 1 diabetes, ESRD, end-stage renal disease.

Interestingly, anti-apoptotic genes (Bcl2, Fas, Nol3) were significantly underexpressed in mini-guts grown from T1D+ESRD crypts as well, as compared to healthy subjects, while the majority of caspases related genes (Caspase 1, 5, 7, 8, 9, 14) were over expressed (FIG. 10G). Moreover, the expression of genes involved in other pro apoptotic pathways was either not altered (i.e. Fas Ligand, FADD, TNF) or inhibited (TRADD) in T1D+ESRD mini-guts. The opposite effect was observed by adding IGF-I (FIG. 4D, FIG. 10H). The absence of alterations in the expression of oxidative stress target genes (Table V) and of any effect of oxidative stress factors (FIG. 10: I-J), confirmed the main apoptotic-related caspase-mediated IGFBP3 mechanism whereby circulating IGFBP3 directly controls CoSCs (FIG. 4E).

TABLE V List of up and down-regulated oxidative stress target genes identified by transcriptomic profiling in CTRL vs. T1D + ESRD freshly isolated colonic crypts and in those cultured with IGFBP3 and IGF-I (at least p < 0.05). Down-regulated genes Up-regulated genes T1D + ESRD DUOX1, PRDX4, STK25, GSS CYBB, GPX5, KRT1, MT3, NOX4, vs. OXR1, PTGS1, SFTPD CTRL CTRL + IGF-I DUOX1, TXNRD AOX1, FTH1, GPX7, GSS, KRT1, vs. LPO, MPO, NCF1, NOS2, NOX4, CTRL OXR1, PTGS1, PTGS2, SCARA3, SFTPD, TPO, TTN CTRL + IGFBP3 NCF1, SOD3 AOX1, GPX5, GPX7, HSPA1A vs. KRT1, MB, MPO, NOX5, OXR1, CTRL PTGS1, SFTPD, TPO, TTN, TXNRD2, UCP2 T1D + ESRD + IGF-I DUOX1, EPHX2, MB, MT3, MPO, PRDX4, PRNP, STK25 vs. NCF1, OXR1, PTGS1, T1D + ESRD SOD3, SRXN1 T1D + ESRD + IGFBP3 CYBB, DUOX1, EPHX2 NOS2, STK25 vs. GPX3, GSTP1, HSPA1A T1D + ESRD MGST3, NCF1, NQO1, PRDX6, RNF7, TXN Abbreviations: IGF-I, insulin-like growth factor 1; IGFBP3, insulin-like grwth factor binding protein 3, CTRL, healthy subjects, T1D, type 1 diabetes, ESRD, end-stage renal disease.

Manipulation of the Circulating IGF-I/IGFBP3 Dyad Alters the Course of Diabetic Enteropathy in a Preclinical Model

In order to further demonstrate the relevance of IGF-I/IGFBP3 circulating factors in vivo, the inventors tested the effects of IGF-I and IGFBP3 administration in a preclinical model of DE.

After 8 weeks of chemically-induced diabetes (using streptozotocin [STZ]), C57BL/6 (B6) mice showed a reduced number of crypts in the colorectal tissue (FIG. 4F), which displayed increased depth and width in more than 70% of cases (FIG. 4: G, H1-H2, I) and a reduced number of Aldh⁺ cells (FIG. 4: J, K1-K2). Interestingly, those mice showed increased serum levels of IGFBP3 and low levels of IGF-I, with lower murine insulin levels as compared to naïve B6 (FIG. 11: A-C). Intraperitoneal (i.p.) administration of IGFBP3 in naïve B6 mice resulted in a reduction in local crypt numbers (FIG. 4: F, H3), with the majority of crypts showing increased depth and width (FIG. 4: G, H3, I) and significant reduction in Aldh⁺ cells as compared to untreated mice (FIG. 4: J, K3). Those features were aggravated by IGFBP3 administration to STZ-treated B6 mice (FIG. 11: D-G, H1-H2), with evidences of weight decrease (FIG. 11J), CoSCs loss (FIG. 11: J-L) and up regulated expression of Caspase 8 and 9 (FIG. 11: M-N). Administration of IGF-I i.p in STZ-treated B6 mice only partially improved mucosa morphology increased the number of normal crypts, which remained abnormal (FIG. 11D), and only partially restored the number of Aldh⁺ cells (FIG. 11: G, H1-H2).

Treatment of Long-Standing T1D with Simultaneous Pancreas-Kidney Transplantation (SPK) Reverts Clinical and Morphological Features of DE

The gold standard treatment for long-standing T1D is SPK, which affords stable glycometabolic control, near-normalize risk factors and prolonged survival (Table VI)(Fiorina et al., 2004; Fiorina et al., 2005; Folli et al., 2010; Secchi et al., 1998; Smets et al., 1999).

TABLE VI Restoration of both normoglycemia and normal renal function in SPK is associated with stable glucose/lipid metabolism and blood pressure control over time at up to 8 years of follow-up as compared to K + T1D (data are shown at 8 years of follow-up). T1D + ESRD SPK K + T1D Parameters (n = 60) (n = 30) (n = 30) P value eGFR <15 65.6 ± 20.2*  61.8 ± 25.2^(§) *, ^(§)<0.0001 (ml/min/1.73 m²) HbA1c (%)  8.4 ± 1.5 5.4 ± 0.3*  7.5 ± 1.4^(§) *<0.0001; ^(§)<0.001 EIR (UI) 37.4 ± 2.3 0* 26.0 ± 7.0^(§) *<0.0001; ^(§)0.001 TG (mg/dl) 162.5 ± 92.7 90.4 ± 23.0* 147.1 ± 98.0^(§) *0.01; ^(§)0.04 Chol (mg/dl) 201.0 ± 45.7 185 ± 27.2  191.1 ± 41.1  Ns LDL (mg/dl) 116.3 ± 40.3 119.5 ± 34.0  97.8 ± 2.1  Ns HDL (mg/dl)  48.1 ± 14.4 51.4 ± 4.1  43.13 ± 5.7   Ns Systolic BP 146.3 ± 18.7 133.1 ± 14.2*  140.1 ± 15.7^(§) 0.03; ^(§)0.04 Diastolic BP 83.7 ± 8.3 79.1 ± 9.2  78.3 ± 9.2  Ns Abbreviations: T1D, type 1 diabetes; ESRD, end stage renal disease; SPK, simultaneous kidney-pancreas transplantation; K + T1D, kidney transplantation alone in type 1 diabetes; eGFR, estimated glomerular filtration rate; HbA1c, glycated hemoglobin; EIR, exogenous insulin requirement; TG, try glycerides; Chol, total cholesterol; LDL, low density lipoprotein; HDL, high density lipoprotein; BP, blood pressure; UI, International Unit.

However, individuals with T1D+ESRD are also treated with kidney transplantation alone but remain diabetic (K+T1D)(Fiorina et al., 2001). A significant improvement in gastrointestinal symptoms was evident over time after SPK in inventors' cohort of transplanted individuals, while the K+T1D group did not report any benefit (FIG. 12: A-C), suggesting that DE is reversible.

Treatment of Long-Standing T1D with SPK Re-Establishes Intestinal Mucosa Morphology and Local Self-Renewal Properties

Analysis of intestinal mucosa samples showed a significant recovery in the structure of the epithelial compartment, with compensatory epithelial hyperplasia in the SPK group (FIG. 12: D1-D2). Recovery of normal crypt histology and number was evident in the SPK group when long-standing T1D was successfully treated while none of these features were evident in individuals who received kidney transplant only and remained diabetic (FIG. 12: D1-D2). Epithelial cell proliferation (MIB1⁺ cells) increased after SPK over time as compared to baseline and to K+T1D at each timepoint (FIG. 4: L, M1-M2), with near-normalization of intestinal morphology, epithelial renewal and neural features (FIG. 12: E1-E2, F, G1-G2, H-I, J1-J2, K). This demonstrates that treatment of long-standing T1D with SPK promoted recovery of intestinal epithelial repair and of self-renewing properties.

Treatment of Long-Standing T1D Promotes Restoration of CoSCs

Treatment of long-standing T1D with SPK is associated with an increase in Aldh⁺ cells (FIG. 4: N, O1-O2) and EphB2⁺ expression in the intestinal crypt (FIG. 4: P, Q1-Q2) and nearly normalizes the percentage of EphB2^(hi+), EphB2⁺hTERT⁺ and EphB2^(hi+)LGR5⁺ cells in isolated intestinal crypts as compared to baseline (FIG. 5: A-C). CoSC marker expression (FIG. 5: D-G) and growth/morphology of mini-guts obtained from SPK individuals were nearly normalized as well (FIG. 5H, FIG. 13: A1-A6). Transcriptome analysis revealed that SPK nearly restored the expression of stem cell and CoSC markers and of pathways involved in preserving CoSCs (FIG. 5I, FIG. 13B, Table VII).

TABLE VII List of up and down-regulated stem cell target genes identified by transcriptomic profiling in SPK as compared to T1D + ESRD freshly isolated colonic crypts (at least p < 0.05). Down-regulated genes Up-regulated genes DVL1 ACTC1 APC CCND2 WNT1 BTRC SOX1 SOX2 ACAN COL1A1 COL2A1 BMP3 CCNE1 CDK1 CXCL2 CD8B MME DLL3 HDAC2 JAG1 DTX2 FGF2 GDF3 ISL1 MSX1 MYO1 GJA1 RB1 h-TERT NCA1 SIGMAR1 PDX1 DHH BGLA P Abbreviations: EGF, epithelial growth factor; FGF, fibroblast growth factor, BMP, bone morphogenetic protein.

It is concluded that treatment of long-standing T1D with SPK promotes restoration of CoSCs.

Treatment of Long-Standing T1D with SPK Restores Circulating IGF-I and IGFBP3

Broad proteomic analysis and targeted immunoassay, revealed a near-normalization of IGFBP3 and IGF-I serum levels after SPK (FIG. 5: J-K) in association with a nearly re-established expression of IGF-IR (FIG. 13C). These results were not evident in the K+T1D group, who showed low levels of IGF-I (FIG. 5J) and IGF-IR expression (FIG. 13C) and only a partial recovery in their IGFBP profile (FIG. 13D). A significant correlation between IGFBP3 serum levels and intestinal symptoms in both SPK and K+T1D groups, but more evident in the latter, confirmed that the restoration of IGFBP3 levels is associated with an improvement in diabetic enteropathy (FIG. 5: L-M, FIG. 14: A-G). Treatment of long-standing T1D with SPK ameliorates diabetic enteropathy via a glucose-associated restoration of the circulating IGF-I/IGFBP3 dyad.

The Ecto-TMEM219 Recombinant Protein Abrogates IGFBP3-Mediated Mini-Gut Destruction In Vitro and Preserves CoSCs In Vivo in a Murine Model of DE.

In order to further demonstrate the IGFBP3-mediated detrimental effects on CoSCs, the inventors generated a recombinant protein based on the TMEM219 extracellular domain (ecto-TMEM219). Addition of ecto-TMEM219 (2:1 molar ratio with IGFBP3) to crypts obtained from CTRL and cultured with IGFBP3 abrogated the pro-apoptotic effect of IGFBP3 on mini-guts and preserved the regenerative properties of crypts to generate mini-guts (FIG. 6A). The expression of CoSC signature markers, EphB2 and LGR5, significantly recovered in mini-guts cultured with IGFBP3 and ecto-TMEM219, emphasizing a favorable effect in preserving CoSCs (FIG. 6B), which was also confirmed in high glucose-cultured mini-guts (FIG. 6A). Moreover, Analysis of Caspase 8 and 9 by RT-PCR documented a net decrease in their expression when ecto-TMEM219 was added to IGFBP3-cultured mini-guts as compared to IGFBP3 alone (FIG. 6: C-D). The inventors then treated STZ-B6 mice with ecto-TMEM219 and observed improved mucosa morphology with recovered number, depth and width of crypts (FIG. 6: E, F, G). Administration of ecto-TMEM219 was associated with an increase in mice body weight as compared to STZ-treated B6 (FIG. 6H), with significant regain of CoSCs (FIG. 6: I-K), a decreased expression of caspase 8 and 9 (FIG. 6: L-M) and a re-establishment of circulating IGFBP3 levels (FIG. 6N).

Discussion

Diabetic enteropathy represents a clinically relevant complication in individuals with T1D, as it is associated with lower quality of life, malnutrition and malabsorbtion (Bytzer et al., 2002; Faraj et al., 2007; Talley et al., 2001). Particularly, in individuals with long-standing T1D (T1D+ESRD), intestinal disorders occur with high frequency and severity (Cano et al., 2007; Wu et al., 2004), resulting in body mass loss and cachexia (Pupim et al., 2005), indicating that enteropathy is an important complication of long-standing T1D (Atkinson et al., 2013; Pambianco et al., 2006). Inventors' results demonstrate that individuals with long-standing T1D experienced severe intestinal disorders (Table VIII) and that these clinical conditions are associated with alterations of the intestinal mucosa, with reduced proliferation of intestinal epithelial cells and with signs of neural degeneration.

TABLE VIII Overview of results of diabetic enteropathy assessment in T1D + ESRD individuals as compared to CTRL and SPK. TID + ESRD SPK vs. vs. Results CTRL TID + ESRD Metabolic Evaluation Glucose metabolism −−− +++ Lipid metabolism −− + Blood pressure control −− + Intestinal Symptoms Diarrhea −−− +++ Abdominal pain −−− +++ Constipation −−− ++ Anorectal Manometry Resting tone = = Contracting tone −− = Reflex response −− = Urgency volume −− ++ Mucosa Epithelial Renewal Proliferation −−− +++ Differentiation −−− +++ Neural Regeneration Nerves −−− +++ Schwann cells −−− +++ Colonic Stem Cell Turnover Colonic stem cells −−− +++ Crypt growth −−− +++ Arbitrary unit: +++ (high improvement); ++ (mild improvement); + (slight improvement); = no improvement; −−− (severe worsening); −− (mild worsening), − (slight worsening). Evaluations were performed as follows: T1D + ESRD vs. CTRL, SKP vs. T1D + ESRD, K + T1D vs. SKP. Abbreviations; T1D, type 1 diabetes; ESRD, end stage renal disease; CTRL, healthy subjects; SPK, simultaneous kidney-pancreas transplantation.

Similar features have also been reported in rodent models of T1D and DE (Domenech et al., 2011). Inventors' data, for the first time, link DE to a defect in CoSCs and implicate IGFBP3 as having an important role in the maintenance of intestinal epithelium homeostasis. While hyperglycemia is a prominent feature of T1D, inventors' in vitro studies suggest that this feature cannot fully explain DE and that circulating factors may play an important role. Proteomic analysis led to the identification of IGF-I as an enterotrophic factor involved in the homeostasis of CoSCs. The inventors then confirmed that IGF-I and IGFBP3 control CoSCs and that this axis is dysfunctional in long-standing T1D. Inventors' data indicate that IGF-I acts as a circulating enterotrophic factor that promotes crypt growth and controls CoSCs through IGF-IR, while IGFBP3 can block IGF-I signaling by binding circulating IGF-I and reducing its bioavailability. In addition, and most importantly, the inventors showed that IGFBP3 acts through a pro-apoptotic IGF-I-independent mechanism on CoSCs, which the inventors demonstrated express TMEM219 (the IGFBP3 receptor), thereby inducing the failure of mini-gut growth. This latter effect is Caspase 8 and 9-mediated and TMEM219-dependent; indeed, the absence of the IGFBP3 receptor (TMEM219) on CoSCs greatly diminished high glucose-associated CoSC injuries. T1D together with starvation and cachexia are characterized by low circulating IGF-I levels (Bondy et al., 1994; Giustina et al., 2014) due to reduced hepatic IGF-I release, which is controlled and stimulated by endogenous insulin (Le Roith, 1997; Sridhar and Goodwin, 2009). More importantly, hyperglycemia appeared to have a direct effect on hepatic synthesis and release of IGFBP3. IGFBP3 may thus act as a hepatic hormone that reduces intestinal absorptive capacity during hyperglycemia. Interestingly, SPK provided a proof of concept to the inventors' hypothesis and supported their findings regarding the existence of circulating factors that control CoSCs. The striking improvement of clinical and functional features of DE that the inventors observed in their study, associated with replenishment of the CoSCs and with restoration of the circulating IGF-I and IGFBP3, strengthens inventors' hypothesis. Finally, the newly generated ecto-TMEM219 recombinant protein improved DE in diabetic mice in vivo and restored the ability of mini-guts to grow normally in vitro, thus confirming the role of IGFBP3 in controlling CoSCs and paving the way for a novel potential therapeutic strategy. In summary, inventors' study shows that an IGFBP3-mediated disruption of CoSCs linked to hyperglycemia is evident in DE. The inventors suggest that circulating IGF-I/IGFBP3 represent a hormonal dyad that controls CoSCs and a novel therapeutic target for individuals with intestinal disorders, in particular caused by diabetes mellitus of long duration (Bondy et al., 1994; Bortvedt and Lund, 2012; Boucher et al., 2010).

Example 2 Materials and Methods Patients and Study Design

60 individuals with T1D+ESRD registered on the waiting list for simultaneous pancreas-kidney transplantation (SPK) matched for (age 41 to 43 years old), gender, and duration of T1D (29.4±1.8 years) were enrolled in the study. 20 subjects affected by type 1 diabetes (T1D) from 10 to 20 years were enrolled as well. 20 healthy subjects matched for age and gender (CTRL), with normal renal function and normal glycometabolic parameters, were studied as well. T1D+ESRD subjects were all on intensive insulin treatment at the time of enrollment in the study, while the CTRL group was not being administered any medication. All T1D+ESRD subjects were on the same treatment as antiplatelet therapy (ASA) and anti-hypertension (angiotensin-converting-enzyme inhibitors), while 40 out of 60 received statins when enrolled in the study. Subjects with clear signs of inflammatory bowel diseases as well as celiac disease were not enrolled.

T1D+ESRD individuals were followed up for 8 years (mean follow-up: 8.6±1.1 years) after receiving either SPK (n=30) or K+T1D (n=30) transplantation according to the macroscopic surgical evaluation at the time of transplantation. Individuals taking an oral anticoagulant agent were not included. SPK individuals were all insulin-independent for the entire follow-up period, whereas K+T1D individuals were on intensive subcutaneous insulin therapy. All subjects provided informed consent before study enrollment. Studies not included in the routine clinical follow-up were covered by an appropriate Institutional Review Board approval (Enteropatia-trapianto/01 Secchi/Fiorina).

IGFBP3 Assessment in Urine and Serum

Serum was collected from 3 ml of fresh blood after centrifugation. Urine samples were collected fresh, centrifuged and stored at −80° C. IGFBP3 levels of all groups of subjects were assessed in frozen samples of serum and urine using commercially available ELISA kits, according to the manufacturer's instructions (R&D).

Statistical Analysis

Correlation analysis and graphs were performed using Prism Graphpad software. Correlation analysis included assessment of IGFBP3 levels in serum vs. urine of individuals evaluated, IGFBP3 serum levels vs. estimated glomerular filtration rate (eGFR). Statistical significance was considered when p value was <0.05.

Measurement of Renal Function and Glycometabolic Parameters

MDRD formula was used to assess estimated glomerular filtration rate (eGFR) in ml/min/m2. Blood tests included assessment of Creatinine, blood glucose, glycated hemoglobin in all subjects

enrolled in the study focusing on comparing CTRL with T1D individuals and individuals with longstanding T1D (T1D+ESRD).

Results

Serum IGFBP3 Levels Correlates with Urinary IGFBP3 Levels

Analysis of serum and urine levels of IGFBP3 in all subjects enrolled in the study documented a significant increase of both serum (FIG. 7A) and urine (FIG. 7B) levels of IGFBP3 in T1D+ESRD subjects as compared to CTRL and to a lesser extent to T1D individuals. A significant correlation between urine levels and serum levels of IGFBP3 was observed in all subjects evaluated (FIG. 7C). Higher levels of serum IGFBP3 correlate with higher levels of urinary IGFBP3. In order to exclude that this might be related to renal function, a correlation between IGFBP3 serum levels and renal function (eGFR) was performed. IGFBP3 serum levels were significantly higher in subjects with ESRD (eGFR<15 ml/min/m2) (FIG. 7D). However, subjects with an eGFR>15 ml/min/m2, thus not affected by ESRD, regardless the presence and history of T1D, did not show any statistical significant correlation between eGFR and IGFBP3 serum levels (FIG. 7E). Considering the correlation between IGFBP3 urinary vs. serum levels in CTRL and comparing their means and medians values within the 250 and 750 percentiles, inventors may set up a range for urinary IGFBP3 as following:

<350 pg/ml: normal levels (levels observed in healthy subjects)

350-500 pg/ml: altered levels (levels observed in T1D with a history of disease <5 years)

>500 pg/ml: indicative of enteropathy (levels observed in long-standing T1D, T1D subjects with other T1D complications, history of T1D>5 years).

The inventors can also identify a normal range of urinary IGFBP3 levels (<350 pg/ml) by considering its correlation with serum IGFBP3 levels as represented in the gray area in FIG. 7F.

Example 3

Five individuals with long-term inflammatory bowel disease (IBD) were enrolled and screened for peripheral levels of IGFBP3, IGF-1 and the ratio of the IGFBP-3/IGF-1, according to the same method described above for the analysis of diabetic samples.

It was found that while IGFBP3 was slightly increased, the levels of IGF1 were severely reduced with an overall alteration of IGFBP3/IGF1 ratio (FIG. 18). Thus in inflammatory bowel disease, a large amount of IGFBP3 is free and available to exert its toxic effect on the intestinal stem cells.

Consequently, an inhibitor of IGFBP3 is also beneficial for the treatment and/or prevention of inflammatory bowel diseases.

Example 4 Material and Methods Patients and Study Design

Sixty serum samples from individuals with type 1 (T1D), with T1D of long (>15 years) duration (long-standing T1D) and healthy volunteers (CTRL) matched for age and gender were obtained from blood collection at the San Raffaele Hospital. Twenty serum samples from individuals screened positive for islets Autoantibodies test were collected at the collaborating site of Gainsville (Florida). 235, 200 and 81 serum samples from normal glucose tolerant (NGT), impaired glucose tolerant (IGT) and type 2 diabetes (T2D) individuals were collected from University of Pisa (Italy) under the Genfiev protocol study. NGT, IGT, and T2D were determined based on the results of OGTT test according to the ADA 2003 criteria.

T1D and long-standing T1D subjects were all on intensive insulin treatment at the time of enrollment in the study, while the CTRL group was not being administered any medication. All T1D subjects were on the same treatment as antiplatelet therapy (ASA) and anti-hypertension (angiotensin-converting-enzyme inhibitors). Concomitant treatment, inclusion and exclusion criteria have been already described (Diabetes Care 2015) and reported at the following website https://clinicaltrials.gov/ct2/show/record/NCT00879801?term=GENFIEV.

All subjects provided informed consent before study enrollment. Studies not included in the routine clinical follow-up were covered by an appropriate Institutional Review Board approval (Enteropatia-trapianto/01 Secchi/Fiorina).

Pancreatic Islets

The human islets used in this study were isolated from cadaveric organ donors according to the procedure already described (Petrelli et al., 2011) in conformity to the ethical requirements approved by the Niguarda Cà Granda Ethics Board. Briefly, islets were isolated using the automated method already described (D'Addio et al., 2014). Two types of enzymes were used: collagenase type P (1-3 mg/ml) and liberase (0.5-1.4 mg/ml) (Roche, Indianapolis, Ind., USA). Islets were purified by discontinuous gradient in syringes (density gradient: 1,108; 1,096; 1,037: Euroficoll, (Sigma-Aldrich, Milan, Italy), or by continuous gradient with refrigerated COBE processor as previously described (Nano et al., 2005). After isolation, islets were cultured at 22° C. in a humidified atmosphere (5% CO₂), in M199 medium (Euroclone, Celbio, Milan, Italy) or CMRL (Mediatech, Cellgro, Va., USA) supplemented with 10% FCS, 100 U/ml penicillin, 100 μg/ml streptomycin sulphate (Euroclone, Celbio) and 2 mmol/l glutamine (Mediatech, Cellgro, Va., USA). In vitro characterisation and culture of islets was performed on islet material processed within 72 h after isolation. Islets were cultured in CMRL 10% FCS, supplemented with 100 μg/ml streptomycin sulphate (Euroclone, Celbio) and 2 mmol/l glutamine (Mediatech, Cellgro, Va., USA) with a glucose concentration of 5 mM for 4 days. Murine islets were kindly provided by Prof. James Markmann (Transplantation Unit, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston) (Ben Nasr et al., 2015b; Vergani et al., 2010). Pancreatic islets were isolated from C57B16/J mice by collagenase digestion followed by density gradient separation and then hand-picking, as described previously (Forbes et al., 2010). Islets were then plated and cultured in RPMI 1640 medium supplemented with L-glutamine, penicillin and 10% as already described, with a glucose concentration of 5 mM for 4 days.

Beta Cell Lines

Mouse βTC3 and αTC1 cells were kindly provided by Carla Perego, University of Milan, with the permission of Prof. Douglas Hanahan (Department of Biochemistry and Biophysics, University of California, San Francisco, Calif.)(Di Cairano et al., 2011). βTC3 were cultured in RPMI 1640 medium (Sigma) containing 0.1 mM glutamic acid and supplemented with 0.7 mM glutamine as described (Di Cairano et al., 2011). The glucose concentration was 11 mM for cell lines.

Pathology and Immunohistochemistry

Samples were fixed in buffered formalin (formaldehyde 4% w/v and acetate buffer 0.05 M) and routinely processed in paraffin wax. 3 m-thick sections of each enrolled case were stained with Hematoxylin & Eosin (H&E) for morphological evaluations. For immunohistochemistry, 3 m-thick sections were mounted on poly-L-lysine coated slides, deparaffinized and hydrated through graded alcohols to water. After antigen retrieval, performed by dipping sections in 0.01 M citrate buffer, pH 6 for 10 minutes in a microwave oven at 650 W as well as endogenous peroxidase activity inhibition, performed by dipping sections in 3% hydrogen peroxide for 10 minutes, incubation with primary antibodies was performed at 4° C. for 18-20 hours, followed by the avidin-biotin complex procedure. Immunoreactions were developed using 0.03% 3,3′diaminobenzidine tetrahydrochloride, and then sections were counterstained with Harris' hematoxylin. The following antibodies were used: insulin (Dako, A0564), anti-IGFBP3 primary antibody (polyclonal, 1:50 dilution, Sigma Aldrich HPA013357) and anti-TMEM219 primary antibody (polyclonal, 1:100, Sigma HPA059185). These antibodies were immunohistochemically tested in pancreatic tissues of healthy subjects, B6 and NOD mice and in liver biopsies of patients with T1D/T2D, islet transplanted patients who did not achieve insulin independence. Tissues without pathological findings were used as controls. All of these tissue samples came from the files stored at the Unit of Pathology of the Department of Biomedical, Biotechnological, and Translational Sciences, University of Parma, Parma, Italy. The immunostaining intensity was graded as 1 (mild), 2 (moderate), and 3 (strong), while its diffusion as 1 (focal), 2 (zonal), and 3 (diffuse).

Immunoflurescence

Immunofluorescence samples were observed using a confocal system (Leica TCS SP2 Laser Scanning Confocal). Images were acquired in multitrack mode, using consecutive and independent optical pathways. The following primary antibodies were used for staining of human tissues/cells: mouse monoclonal anti-caspase cleavage product of cytokeratin 18 M30 (clone M30, Hoffmann-LaRoche, Basel, Switzerland), rabbit polyclonal IGFBP3 (1:250, Sigma, HPA013357), rabbit polyclonal TMEM219 (1:250, Sigma, HPA059185) and Guinea Pig polyclonal insulin (1:50, DAKO, A0564). The following primary antibodies were used for staining of murine tissues/cells: rabbit polyclonal IGFBP3 (1:250, Sigma, SAB4501527), goat polyclonal TMEM219 (1:50, Santa Cruz, 244405), Guinea Pig polyclonal insulin (1:50, DAKO, A0564). The following secondary antibodies were used for staining of human tissues/cells: donkey anti-rabbit FITC (Jackson) and donkey anti-guinea pig TRITC (Jackson). The following antibody was used for staining of murine tissues/cells: donkey anti-goat FITC (Jackson).

Human and murine pancreatic islets co-cultured with/without IGFBP3 (Life Technologies, 10430H07H5), with/without ecto-TMEM219 (generated by us in collaboration with Genscript, 130 ng/ml), with/without high glucose (20 mM Glucose), with/without IFN-γ and IL-1β (R&D Systems, Minneapolis, Minn. 201-LB-005, 2 ng/ml and PeProTech, 300-O2, 1,000 U/ml), were stained with TMEM219, insulin and M30 for immunofluorescence for co-localization studies. Murine beta cells co-cultured in the same conditions as pancreatic islets, were fixed in 10% neutral buffered for 30 min, washed with PBS three times and permeabilized with PBS—BSA 2% triton ×100 0.3% for 20 min, blocked with serum 10%, and finally incubated with primary antibodies over-night at 4° C. and subsequently labeled with fluorescent secondary antibodies for 2 hour at room temperature. Primary and secondary antibodies were selected as described above.

Islets and Beta Cells In Vitro Studies and Characterization Culturing Conditions

Human and murine islets were cultured at different glucose concentration (5 mM, 20 mM, Sigma), with/without inflammatory stimuli/cocktail (IFN-γ+IL-1β, 2 ng/ml R&D Systems and 1,000 U/ml Peprotech, respectively), with/without IGFBP3 (Life Technologies, 50 ng/ml), with/without ecto-TMEM219 (130 ng/ml, see Recombinant proteins and interventional studies) and islets were collected for immunofluorescence studies, RNA extraction, apoptosis detection, and protein analysis. Supernatants were collected for assessment of insulin, IGFBP3 and IGF-I secretion.

β-TC were cultured as previously described, with/without inflammatory stimuli/cocktail (IFN-γ+IL-1β), with/without IGFBP3, with/without ecto-TMEM219 (see Recombinant proteins and interventional studies) and cells were collected as for islets studies.

Immunoblotting

Total proteins of intestinal bioptic samples were extracted in Laemmli buffer (Tris-HCl 62.5 mmol/l, pH 6.8, 20% glycerol, 2% SDS, 5% b-mercaptoethanol) and their concentration was measured. 35 mg of total protein was electrophoresed on 7% SDS-PAGE gels and blotted onto nitrocellulose (Schleicher & Schuell, Dassel, Germany). Blots were then stained with Ponceau S. Membranes were blocked for 1 h in TBS (Tris [10 mmol/1], NaCl [150 mmol/1]), 0.1% Tween-20, 5% non-fat dry milk, pH 7.4 at 25° C., incubated for 12 h with a rabbit polyclonal IGFBP3 antibody (Sigma, HPA013357) diluted 1:250, or goat polyclonal TMEM219 (Santa Cruz Biotechnology, 244404 or 244405) diluted 1:200 or with a monoclonal mouse anti-b-actin antibody (Santa Cruz Biotechnology) diluted 1:500 in TBS-5% milk at 4° C., washed four times with TBS-0.1% Tween-20, then incubated with a peroxidase-labeled mouse anti-rabbit IgG secondary antibody (DAKO) (for IGFBP3) or rabbit anti-goat (for TMEM219) or rabbit anti mouse for b-actin, diluted 1:1000 (Santa Cruz Biotechnology) in TBS-5% milk, and finally washed with TBS-0.1% Tween-20. The resulting bands were visualized using enhanced chemiluminescence (SuperSignal; Pierce, Rockford, Ill., USA).

qRT-PCR Analysis

RNA from purified intestinal crypts was extracted using Trizol Reagent (Invitrogen), and qRT-PCR analysis was performed using TaqMan assays (Life Technologies, Grand Island, N.Y.) according to the manufacturer's instructions. The normalized expression values were determined using the ΔΔCt method. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) data were normalized for the expression of ACTB, and ΔCt values were calculated. Statistical analysis compared gene expression across all cell populations for each patient via one-way ANOVA followed by Bonferroni post-test for multiple comparisons between the population of interest and all other populations. Statistical analysis was performed also by using the software available RT² profiler PCR Array Data Analysis (Qiagen). For two groups comparison Student t test was employed. Analysis was performed in triplicates before/after 3 days of culture. Below are reported the main characteristics of primers used for human genes:

Gene Refseq Band Size Reference Symbol UniGene # Accession # (bp) Position INS Hs.272259 NM_000207.2 126 252 IGF-IR Hs.643120 NM_000875.3 64 2248 TMEM219 Hs.460574 NM_001083613.1 60 726 LRP1 Hs.162757 NM_002332.2 64 656 TGFbR1 Hs.494622 NM_001130916.1 73 646 TGFbR2 Hs.604277 NM_001024847.2 70 1981 CASP8 Hs.599762 NM_001080124.1 124 648 ACTB Hs.520640 NM_001101 174 730

Below are reported the main characteristics of primers used for murine genes:

Gene Refseq Band Size Reference Symbol UniGene # Accession # (bp) Position INS Mm.4626 NM_008386.3 80 533 IGF-IR Mm.275742 NM_010513.2 106 3901 TMEM219 Mm.248646 NM_026827,1 78 677 LRP1 Mm.271854 NM_032538.2 104 2995 TGFbR1 Mm.197552 NM_009370.2 85 90 TGFbR2 Mm.172346 NM_033397.3 132 1656 Casp8 Mm.336851 NM_001080126.1 96 1525 GAPDH Mm. 304088 NM_008084.2 107 75

ELISA Assay

IGF-I and IGFBP3 levels in the pooled sera/plasma of all groups of subjects and in all groups of treated and untreated mice were assessed using commercially available ELISA kits, according to the manufacturer's instructions (R&D SG300, and Sigma RAB0235).

Human primary hepatocytes (HEP10™ Pooled Human Hepatocytes, ThermoFisher Scientific) were cultured for 3 days in Williams Medium as per manufacturer's instructions at different glucose concentrations: 11 mM, 20 mM and 35 mM. Culturing supernatant was collected, and IGFBP3 was assessed using an IGFBP3 ELISA kit (Sigma, RAB0235) according to the manufacturer's instructions. Collected cells were separated by trypsin and counted with a hemacytometer.

Insulin levels were assayed with a microparticle enzyme immunoassay (Mercodia Iso-Insulin ELISA, 10-1113-01) with intra- and inter-assay coefficients of variation (CVs) of 3.0% and 5.0%.

Recombinant Proteins and Interventional Studies

Recombinant human IGF-I (Sigma, 13769), 100 ng/ml (IGF-I), recombinant human IGFBP3 (Life Technologies, 10430H07H5), 50 ng/ml (IGFBP3), anti-IGF-IR (Selleckchem, Boston, OSI-906), 1 μM/L and ecto-TMEM219 (D'Addio et al., 2015), 130 ng/ml were added to islets/cell cultures at day +1 from islets collection/cell culture. Pancreatic islets and beta cells were also exposed to complex diabetogenic conditions: 20 mM glucose, the mixture of 2 ng/ml recombinant human IL-1β (R&D Systems, Minneapolis, Minn. 201-LB-005), and 1,000 U/ml recombinant human IFN-γ (PeProTech, 300-O2) for 72 h.

IGFBP3 (Reprokine, Valley Cottage, N.Y.) was administered to naive B6 mice at 150 μg /mouse/day for 15 days intraperitoneally (i.p.); ecto-TMEM219 was administered in vivo to STZ-treated B6, to 10 weeks old NOD and to B6 fed a high fat diet (HFD-B6) mice intraperitoneally (i.p.) at a dose of 150 μg/mouse/day for 15 days in STZ-treated B6 and in NOD, and 100 μg/mouse every other day for 8 weeks in HFD-B6 mice.

Animal Studies

Male C57BL/6 (B6) mice and female non-obese diabetic (NOD) mice (4 weeks old and 10 weeks old) were obtained from the Jackson Laboratory, Bar Harbor, Me. All mice were cared for and used in accordance with institutional guidelines approved by the Harvard Medical School Institutional Animal Care and Use Committee. B6 mice were rendered diabetic using a chemical approach with streptozotocin (STZ) injection (225 mg/kg, administered i.p.; Sigma S0130) this model is accepted and validated as a model of T1D diabetes (Carvello et al., 2012; Petrelli et al., 2011; Vergani et al., 2013). Diabetes was defined in both STZ-treated B6 and NOD as blood glucose levels >250 mg/dL for 3 consecutive measures.

To study the onset and progression of T2D, B6 mice (6 weeks old) were housed in a germfree Animal house in accordance with the Principles of Laboratory Animal Care (NIH Publication No 85-23, revised 1985) and received water and food ad libitum. The study protocol was approved by the local ethics committee. Mice were fed with either a High Fat Diet (HFD) (DIO diet D12492, 60% of total calories from fat) or a normal-fat diet (NFD; DIO diet D12450B; 10% of total calories from fat), purchased from Research Diets (Mucedola, Settimo Milanese, Italy). Each group of treatment or control consisted of 10 animals. After 16 weeks, glycemia was measured and IV glucose tolerance test (IVGTT) was performed. The next day, mice were anaesthetized and then a blood sample was obtained and pancreas was harvested for histology studies. A portion of the tissue was also snap-frozen and stored in Trizol to perform RT-PCR studies.

Finally, plasma and serum were collected to perform analysis of IGF-I (IGF-I ELISA kit, R&D MG100), IGFBP3 (IGFBP3 ELISA kit, R&D MGB300) and insulin levels (Mouse Insulin ELISA kit, Mercodia, 10-1247-O1). Blood glucose was monitored twice per week up to 12 weeks in HFD-B6 in order to confirm diabetes onset and permanence.

Statistical Analysis

Data are presented as mean and standard error of the mean (SEM) and were tested for normal distribution with the Kolmogorov-Smirnov test and for homogeneity of variances with Levene's test. The statistical significance of differences was tested with two-tailed t-test and the chi-square (χ²) tests. Significance between the two groups was determined by two-tailed unpaired Student's t test. For multiple comparisons, the ANOVA test with Bonferroni correction was employed. All data were entered into Statistical Package for the Social Science (SPSS®, IBM®, SPSS Inc., Chicago, Ill.) and analyzed. Graphs were generated using GraphPad Prism version 5.0 (GraphPad Software, La Jolla, Calif.). All statistical tests were performed at the 5% significance level.

Results IGFBP3 Peripheral Levels are Increased in Pre-Diabetic and Diabetic Mice.

In order to identify potential circulating factors that may have a role in inducing beta cell death, the inventors profiled the serum proteome of healthy subjects and individuals at risk for T1D, based on the presence of one or more anti-islets autoantibodies, using an unbiased proteomic approach. Proteins, which were significantly different (p-value<0.01) in control pool versus individuals at risk for T1D pool, were further submitted to hierarchical clustering analysis. A clear proteomic profile was evident in individuals at risk for T1D (and in overtly T1D as well) as compared to healthy subjects, with more than 50% of the detected proteins segregating in either one group or the other. In particular, the levels of IGF-I binding proteins 3 (IGFBP3) were increased in individuals at risk for T1D using an immune-targeted assay (FIG. 19A), and thus preceded the onset of hyperglycemia. Interestingly, IGFBP3 levels were also altered in samples obtained from the Genfiev Study, which enrolled more than 800 individuals, and classified them based on the results of the OGTT test in three main categories: normal glucose tolerant (NGT), impaired glucose tolerant (IGT) subjects and T2D individuals (T2D). The inventors observed that IGFBP3 levels were increased in IGT and T2D as compared to NGT subjects, confirming that high peripheral levels of IGFBP3 mainly characterized pre-diabetic conditions (FIG. 19B). To demonstrate the detrimental effect of IGFBP3 on islets and beta cells, the inventors first demonstrated that pre-diabetic NOD mice as well as diabetic NOD mice and streptozotocin-induced diabetic C57BL/6 mice (STZ-B6) exhibited increased peripheral IGFBP3 levels as compared to naïve B6 (FIG. 20A). The inventors then confirmed this in a murine model of T2D, the HFD model. C57B16/J (B6) mice fed a high fat diet, which develop T2D in 16 weeks, showed increased levels of peripheral IGFBP3 as compared to B6 mice fed a normal fat diet (FIG. 20B).

Increased IGFBP3 Production by Hepatocytes in Inflamed Environment and in T1D.

Liver is known to be a site of IGFBP3 production. In order to explore if inflammatory stimuli could influence hepatic IGFBP3 production, the inventors cultured human primary hepatocytes with various cytokines and with different glucose concentrations (11, 20 and 35 mM) and demonstrated that IGFBP3 levels in the supernatants increased rapidly following different pro-inflammatory stimuli and increased glucose levels (FIG. 21: A-B).

TMEM219 is Expressed in Human Islets.

In order to evaluate the effect of IGFBP3/TMEM219 axis on islets and beta cells, the inventors first assessed TMEM219 expression by using immunofluorescence and its co-localization with insulin at the confocal microscopy (FIG. 22: A1-A2). Human islets obtained from cadaver donors whose pancreas were not suitable for organ donation were studied. TMEM219 (green staining) is diffusely expressed within islets and co-localize with insulin (red staining) (FIG. 22: A1-A2). The inventors further evaluated the expression of the other known receptors for IGFBP3 (i.e. LPR1, TGF-βR1 and TGF-βR2) but none appeared expressed (FIG. 22B). The inventors then confirmed TMEM219 expression by using RT-PCR and WB (FIG. 22: B-C).

The inventors further proved expression of TMEM219 in murine islets using RT-PCR and excluded that of other known IGFBP3 receptors (LRP1, TGF-beta type 1 and TGF-beta type 2) already described in other cells and models (Baxter, 2013; Forbes et al., 2010) (FIG. 23A). Finally, the inventors made use of the availability of murine beta and alpha cell lines (αTC and βTC), and determined by RT-PCR that expression of TMEM219 is restricted to beta cells while other islet cells, such as alpha cells, do not express it (FIG. 23B) and further confirm TMEM219 expression by WB (FIG. 23C). Immunofluorescence staining of TMEM219 (green) and its co-localization with insulin was also confirmed on beta cell line at the confocal microscope (FIG. 23D).

IGFBP3 Damages a Beta Cell Line In Vitro.

To demonstrate that IGFBP3 targets beta cells within the islets, the inventors cultured a beta cell line (βTC) for 3 days with/without IGFBP3. By using a viability/apoptosis assay, the inventors were able to demonstrate a reduced percentage of viable beta cells in IGFBP3-treated conditions as compared to untreated (FIG. 24A). Interestingly, IGFBP3-treated beta cells also showed a significant increase in caspase8 expression (FIG. 24B) and a reduction in insulin expression by both immunofluorescence and RT-PCR (FIG. 24: C, D1-D2, E). Interestingly, IGFBP3-induced apoptosis was markedly higher than that induced by the pro-inflammatory stimuli IL-1β and IFN-γ (FIG. 24: A-B) and insulin expression and release were only slightly reduced (FIG. 24: C-E).

IGFBP3 Damages Murine Islets In Vitro.

To further demonstrate the IGFBP3-mediated detrimental effect on islets, the inventors cultured murine islets isolated from C57BL/6 mice for 4 days with/without IGFBP3. The appearance of extensive apoptosis as assessed by FACS (Annexin V⁺7AAD⁻) documented that IGFBP3-treated islets undergo early apoptosis (87±2 vs. 67±2%, p=0.004), associated with an increase in caspase 8 expression and with a decrease in insulin expression by RT-PCR (FIG. 25: A-C).

IGFBP3 Damages Human Islets In Vitro.

The inventors finally confirmed the IGFBP3-mediated detrimental effects in human islets by demonstrating that in vitro cultured human islets, obtained from cadaver donors whose pancreata were not suitable for organ donation, exposed to IGFBP3 for 4 days underwent greatly to apoptosis (FIG. 26A), showed an increase in caspase 8 expression (FIG. 26B) and an increased expression of M30 (FIG. 8: C1-C2), a marker for apoptosis, associated with a decrease in insulin expression at immunostaining (FIG. 26:D1-D2) and using RT-PCR (FIG. 26E).

IGFBP3 Injection in C57BL/6 Mice Alters Islet Morphology In Vivo.

In order to confirm that IGFBP3 alters islet morphology, the inventors injected recombinant IGFBP3 (Reprokine) in naïve B6 and STZ-treated B6 mice (150 μg every day for 15 days). Histology (H&E) analysis of collected pancreata demonstrated an increased derangement in islets of STZ-B6 IGFBP3-treated mice as compared to islets of naïve and STZ-B6 mice, confirmed by scattered insulin expression upon immunostaining (FIG. 27: A1-A6).

The Recombinant Protein Ecto-TMEM219 Prevents IGFBP3-Associated Damage in a Beta Cell Line In Vitro.

To demonstrate that ecto-TMEM219 prevents IGFBP3-associated detrimental effects specifically on beta cells, the inventors cultured a beta cell line with IGFBP3 and ecto-TMEM219 and observed that beta cell apoptosis was greatly reduced by the addition of ecto-TMEM219. The effect was also confirmed by the analysis of caspase 8 expression which appeared reduced in IGFBP3+ecto-TMEM219-treated beta cells as compared to those cultured with IGFBP3 only (FIG. 28: A-B). Insulin expression, as assessed by RT-PCR and immunofluorescence (red), was consistently increased by the addition of ecto-TMEM219 to IGFBP3-cultured beta cells (FIG. 28: C1-C3).

The Recombinant Protein Ecto-TMEM219 Prevents IGFBP3-Associated Detrimental Effects in Murine Islets In Vitro.

In order to further confirm the therapeutic properties of ecto-TMEM219 in preventing IGFBP3-associated damage, the inventors tested the effect of ecto-TMEM219 in cultured murine islet in vitro. The addition of ecto-TMEM219 (2:1 molar ratio with IGFBP3) to isolated C57BL/6 islets co-cultured with IGFBP3 abrogated the pro-apoptotic effect of IGFBP3. Moreover, caspase 8 expression was significantly reduced in islets cultured with IGFBP3 and ecto-TMEM219 (FIG. 29A). Insulin expression was increased by the addition of ecto-TMEM219 to murine islets cultured with IGFBP3 (FIG. 29B), emphasizing a favorable effect of ecto-TMEM219 on preserving islet function.

The Recombinant Protein Ecto-TMEM219 Prevents IGFBP3 Detrimental Effects on Human Islets In Vitro.

To demonstrate the beneficial effects of ecto-TMEM219 in preventing islets destruction, the inventors cultured human islets with IGFBP3 and ecto-TMEM219 for 4 days and the inventors demonstrated a rescue of IGFBP3-mediated islets damaging by ecto-TMEM219, associated with an increase of insulin expression and a decrease of caspase 8 expression at RT-PCR (FIG. 30: A-B).

Interestingly, the co-staining of insulin (red) and M30 (green), a marker for apoptosis, confirmed that insulin-producing cells were protected by ecto-TMEM219 during the co-cultured with IGFBP3 (FIG. 30: C1-C3).

The Recombinant Protein ectoTMEM219 Prevents IGFBP3-Associated Islet Alterations.

In order to prove the effect of ecto-TMEM219 in the treatment of diabetes, the inventors measured insulin serum levels in STZ-treated diabetic mice at 8 weeks and observed that insulin was significantly increased in those mice that were treated with ecto-TMEM219 (i.p. 150 μg every other day for 2 weeks) as compared to untreated STZ-B6 (FIG. 31A). Finally, in another model of islet injury in vivo, B6 mice fed with a high fat diet (B6-HFD) showed altered blood glucose and insulin levels, while B6-HFD treated with ecto-TMEM219 (i.p. 100 μg every other day for 6 weeks) maintained near-normal glucose and insulin levels (FIG. 31B), thus suggesting a curative effect of ecto-TMEM219 in type-1 and type-2 diabetes.

Discussion

Type 1 diabetes (T1D) has historically been regarded as a T cell-mediated autoimmune disease, resulting in the destruction of insulin-producing pancreatic beta cells (Bluestone et al., 2010; Eisenbarth, 1986). According to this perspective, an initiating factor triggers the immune response against autoantigens, and the subsequent newly activated autoreactive T cells target and further destroy insulin-producing beta cells (Bluestone et al., 2010). Whether destruction of beta cells is solely determined by the autoimmune attack or whether other mechanisms such as paracrine modulation, metabolic deregulation and non-immune beta cell apoptosis contribute to T1D pathogenesis is now a matter of debate (Atkinson and Chervonsky, 2012; Atkinson et al., 2015). Recently, it has been observed that environmental factors (e.g.; viral infections, diet, neonatal exposure to milk and microbiota) may be required to initiate the autoimmune response in T1D (Filippi and von Herrath, 2008; McLean et al., 2015). Thus a new approach to study the pathogenesis of T1D is gradually emerging (McLean et al., 2015), such that immunological and genetic factors are no longer considered to be the sole determinant of T1D (Alper et al., 2006; Oilinki et al., 2012). Moreover, the efficacy of immunotherapeutic strategies, which have been considered in the last decade to be the principal prospect for establishing a cure for T1D, is now being questioned (Ben Nasr et al., 2015a). While targeting the autoimmune response using an immunosuppressive treatment or a pro-regulatory regimen was shown to be satisfactory in rodents, such strategies conversely achieved insulin independence in a negligible number of T1D individuals (Atkinson et al., 2015). In addition to underscoring the difference between animal models and humans, these data also shed light on the fact that investigation of the immune response primarily examined immune events occurring in the periphery, while little is known with respect to the disease process that occurs within islets and particularly in beta cells. In this regard, the discovery of novel factors involved in the initiation/facilitation of beta cell loss in T1D will be of significant value. Such discoveries may pave the way for novel therapeutic approaches capable of halting or delaying the very first phase of the disease. In the present invention it was found that in individuals at high-risk for T1D and in those with overt T1D, IGFBP3 peripheral levels are increased. Interestingly a similar pattern was also observed in individuals at risk of developing T2D (IGT, IFG), where glucose intolerance was already detectable, and in those with established T2D, confirming that, despite a different etiology, the mediator of beta cell loss, which occurs in both types of diabetes, may be the same, a betatoxin called IGFBP3. In fact, T1D and T2D are both characterized by a loss of beta cells, which results in a reduced secretion of insulin, failure to control blood glucose levels and hyperglycemia (Brennand and Melton, 2009; Yi et al., 2014). Despite different etiological mechanisms, either autoimmune response in T1D or insulin resistance/inflammation in T2D, lead to a progressive reduction of beta cell mass. Several approaches are currently available to treat T1D and T2D, but none of them aims to target beta cell loss, protect from beta cell injury and preserve beta cell mass, thus preventing diabetes onset. IGFBP3 may also be a mechanism to explain the decompensation observed in patients with T2D, which slowly but steadily lose their beta cell function and stop producing insulin. The chronic IGFBP3 overproduction observed in T2D may favor the destruction of beta cells and lead to the failure for instance of oral anti-diabetic agent. The inventors have also observed that the IGFBP3 receptor (TMEM219) is expressed in murine/human islets, and that its ligation by IGFBP3 is toxic to beta cells, raising the possibility of the existence of an endogenous beta cell toxin (betatoxin) that may be involved in the early phase of T1D and in diabetes in general. A non-immunological factor may determine islet/beta cell injuries, and facilitate the exposure of autoantigens to immune cells, thus creating a local inflamed environment and a sustained immune reaction. Liver has been already documented to be the primary source for IGFBP3, and its exposure to inflammation and high glucose levels significantly increases IGFBP3 release in the circulation. As a result, IGFBP3 targets islets and beta cells thus favoring their damage and loss. Therefore, neutralization of IGFBP3-mediated beta cell injury through the use of newly generated inhibitors of IGFBP3/TMEM219 axis, such as recombinant ecto-TMEM219, may prevent beta cell loss by quenching peripheral IGFBP3, thus blocking its signaling via TMEM219 and halting/delaying T1D progression (FIG. 32). This may lead to clinical application in the field of diabetes prevention, resulting in the use of ecto-TMEM219 in individuals at high-risk for T1D and eventually T2D. Inhibitors of IGFBP3/TMEM219 axis may thus prevent early beta cell injuries associated with the early phase of T1D, by inhibiting binding of IGFBP3 to TMEM219 expressed on the target tissue. Considering its role in preventing early loss of beta cells, inhibitors of IGFBP3/TMEM219 axis may also be considered of benefit in the early treatment of T2D. Therefore, inhibitors of IGFBP3/TMEM219 axis may represent a therapeutic strategy that prevent diabetes onset and protect beta cell from loss and damage thus becoming a relevant clinical option for individuals at risk of developing diabetes, both T1D and T2D, and in those with diabetes in the early stages. Individuals at risk of developing T1D are mainly characterized by the early detection in the serum of multiple autoantibodies against islet peptides, which are usually absent in healthy subjects (Ziegler et al., 2013). These individuals are usually relatives (brothers, sisters) of individuals with T1D, but do not have any sign or symptom related to T1D. The probability of progressing to T1D in these subjects within 10 years is high, with the majority of them (70%) developing T1D in the next 15 years, but are often underestimated (Ziegler et al., 2013). Individuals at risk for developing T2D are difficult to identify, especially in the early phase. Prevention consists mainly of lifestyle modifications, which may delay the onset of the disease but could not prevent it (Schwarz et al., 2012). Various screening methods (genetic analysis, metabolomics profile, obesity and risk factors assessment) to early detect alterations in glucose metabolism are underway, but therapeutic agents capable of preventing or protecting from T2D onset are not available and current options only include anti-diabetic agents that control hyperglycemia and delay T2D progression (metformin), or agents that control other risk factors (lipid-lowering and blood pressure-lowering agents) (Nathan, 2015). Therefore, treatments aiming to reduce the burden of diabetes in the general population, both T1D and T2D, should focus on these high-risk populations. This invention is intended as a new clinical therapeutic agent to be used in individuals at risk for developing diabetes to prevent its onset and in those who are in the early stages of the disease (new-onset) to protect from progression into established diabetes, by counteracting beta cell loss and preserving beta cell mass. Given its role in preventing beta cells loss and damage, inhibitors of IGFBP3/TMEM219 axis are of use in individuals at risk for developing T1D or T2D, and in those with the disease in its early stages.

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1.-19. (canceled)
 20. A method of treating and/or preventing diabetes in a subject, comprising: administering an effective amount of an inhibitor of the IGFBP3/TMEM219 axis to a subject, wherein said inhibitor comprises a fragment of the receptor TMEM219, said fragment comprising an extracellular domain of TMEM219.
 21. The method of claim 20, wherein said inhibitor is a fragment of the receptor TMEM219.
 22. The method of claim 20, wherein said inhibitor is ecto-TMEM219.
 23. The method of claim 20, wherein said inhibitor is soluble.
 24. The method of claim 20, wherein said inhibitor is pegylated.
 25. The method of claim 20, wherein said inhibitor is a host cell genetically engineered to express said fragment of the receptor TMEM219.
 26. The method of claim 20, wherein the diabetes is Type-1 or Type-2 diabetes.
 27. The method of claim 20, wherein the subject is selected from the group consisting of: a subject at risk of developing Type-1 and/or Type-2 diabetes, and a subject with early stage Type-1 and/or Type-2 diabetes.
 28. The method of claim 20, wherein said inhibitor of the IGFBP3/TMEM219 axis is administered as a pharmaceutical composition comprising a pharmaceutically acceptable carrier.
 29. The method of claim 28, wherein said pharmaceutical composition comprises a second therapeutic agent.
 30. The method of claim 29, wherein the second therapeutic agent is selected from the group consisting of: insulin in any form, Pramlintide (Symlin), angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs), Aspirin, Cholesterol-lowering drugs. Metformin (Glucophage, Glumetza, others), Sulfonylureas (glyburide (DiaBeta, Glynase), glipizide (Glucotrol) and glimepiride (Amaryl), Meglitinides (for instance repaglinide (Prandin) and nateglinide (Starlix)), Thiazolidinediones (Rosiglitazone (Avandia) and pioglitazone (Actos) for examples), DPP-4 inhibitors (sitagliptin (Januvia), saxagliptin (Onglyza) and linagliptin (Tradjenta)), GLP-1 receptor agonists (Exenatide (Byetta) and liraglutide (Victoza)), SGLT2 inhibitors, examples include canagliflozin (Invokana) and dapagliflozin (Farxiga).
 31. A method of treating and/or preventing diabetes in a subject, comprising: administering an effective amount of an inhibitor of the IGFBP3/TMEM219 axis to a subject, wherein said inhibitor comprises a polynucleotide coding for a fragment of the receptor TMEM219, said fragment comprising an extracellular domain of TMEM219.
 32. The method of claim 31, wherein said polynucleotide codes for ecto-TMEM219.
 33. The method of claim 31, wherein said inhibitor is soluble.
 34. The method of claim 31, wherein said inhibitor is a vector comprising or expressing said polynucleotide.
 35. The method of claim 31, wherein said inhibitor is a host cell comprising said polynucleotide.
 36. The method of claim 31, wherein the diabetes is Type-1 or Type-2 diabetes.
 37. The method of claim 31, wherein the subject is selected from the group consisting of: a subject at risk of developing Type-1 and/or Type-2 diabetes, and a subject with early stage Type-1 and/or Type-2 diabetes.
 38. The method of claim 31, wherein said inhibitor of the IGFBP3/TMEM219 axis is administered as a pharmaceutical composition comprising a pharmaceutically acceptable carrier.
 39. The method of claim 38, wherein said pharmaceutical composition comprises a second therapeutic agent.
 40. The method of claim 39, wherein the therapeutic agent is selected from the group consisting of: insulin in any form, Pramlintide (Symlin), angiotensin-converting enzyme (ACE) inhibitors or angiotensin II receptor blockers (ARBs), Aspirin, Cholesterol-lowering drugs. Metformin (Glucophage, Glumetza, others), Sulfonylureas (glyburide (DiaBeta, Glynase), glipizide (Glucotrol) and glimepiride (Amaryl), Meglitinides (for instance repaglinide (Prandin) and nateglinide (Starlix)), Thiazolidi nediones (Rosiglitazone (Avandia) and pioglitazone (Actos) for examples), DPP-4 inhibitors (sitagliptin (Januvia), saxagliptin (Onglyza) and linagliptin (Tradjenta)), GLP-1 receptor agonists (Exenatide (Byetta) and liraglutide (Victoza)), SGLT2 inhibitors, examples include canagliflozin (Invokana) and dapagliflozin (Farxiga).
 41. A composition comprising an inhibitor of the IGFBP3/TMEM219 axis, wherein said inhibitor comprises a fragment of the receptor TMEM219 or a polynucleotide coding for said fragment, wherein said fragment comprises an extracellular domain of TMEM219.
 42. The composition of claim 41, wherein said inhibitor is a fragment of the receptor TMEM219.
 43. The composition of claim 41, wherein said inhibitor is ecto-TMEM219.
 44. The composition of claim 41, wherein said polynucleotide codes for ecto-TMEM219.
 45. The composition of claim 41, wherein said inhibitor is a vector comprising or expressing said polynucleotide.
 46. The composition of claim 41, wherein said inhibitor is a host cell genetically engineered to express said fragment of the receptor TMEM219.
 47. The composition of claim 41, wherein said inhibitor is a host cell comprising said polynucleotide
 48. The composition of claim 41, wherein said composition comprises a pharmaceutical composition comprising said inhibitor and a pharmaceutically acceptable carrier.
 49. The composition of claim 48, wherein said pharmaceutical composition comprises a second therapeutic agent. 